This is a boosting switch mode power supply that runs on 12V and outputs approx 300VDC. The 240VAC is created by fast switching the 4 mosfets or groups of mosfets in an H-bridge. Some filtering, smoothing and safety is added. And that's it. To repair: Remove the mosfets. Check them. If one is damaged, order new ones from the same batch for all positions of that section. They should be balanced. Now first, clean up burnt areas, resolve shorts, replace parts that are obviously broken, check small transistors, check the gate resistors, and all other small stuff. If you have one, then connect a 2-channel oscilloscope to the gate connections of both mosfet groups and power up the device using a current-limited 13V supply. You should briefly see nice drive signals, just before the protection powers the thing down again. Turn it off. If you don't have a scope, you can use a good AC multimeter that does not show DC components when measuring AC. Check that by measuring a DC voltage in AC setting. It must show almost 0V. So, at the gate connections you should see an AC voltage, indicating that there is a drive signal. If that is all working, for both mosfet groups, then we can proceed. Now, at each group, you mount one mosfet, so you blow up max 2 mosfets during testing. Connect a small test load and a multimeter to the main capacitors at the secundary side of the transformer: at the main capacitors. Test load can be the two of your smallest 240V incandescent light bulbs in series. Stand back and power up again, briefly. Your test lights should light, and your meter should indicate a significant DC voltage in the capacitors. If not, try again and take attention to your power supply. It might get overloaded by this. In that case, you'll need to use a bigger power supply or a battery. when using a battery, then use a smaller fuse while testing: 10Amps. So... You can proceed with checking drive signals at the high-voltage part. During this, you leave the light bulbs connected. They will discharge the capacitors fast, between every test you do. For safety. Here we do the same: before actually mounting mosfets, we first measure if drive signals are present at the gates. When all good, you can also mount some mosfets at the secondary stage. Connect another small incandescent light bulb to the output and test again. When you ordered your mosfets from China, you should test them before mounting them. If all good, remove the test mosfets and mount all new mosfets. At this point, test again. If all good, remove your test light bulb, reassemble, install the correct fuse(s), test again with a battery and a bigger load. These units can fail with a lot of damage. A mosfet usually fails into a short circuit. That kills the mosfet at the other side, too, probably in a short circuit as well. So now your 12V supply is short circuited. Hopefully, the fuse goes out before the tracks burn off the circuit board. Failing mosfets will often feed quite a lot of current into the drive circuitry, killing that off as well. So, if you just change the mosfets, you're setting yourself up for some more dead mosfets. If your brother uses power tools on these units, you might want to add some more filtering to the output. Add a capacitor of the type you find in those fake power-saving plugs. Thank you for reading until the end.
Good tips there but people shouldn't be buying semiconductors from china. They're all fakes, rebadged or rejects that have been rebranded with anyone's guess as to what they really are.
The process should go -> fuses -> transistors -> diodes ->caps -> resistors -> ic. The cracked component is optron (opto couple probably PC817). Check for shorts on all of the parts and then check for improper open, bulgy caps, diodes should show something only on one side. You can't change zener with diode, those are two different components. Diodes are fast recovery so they should read 150-400, transistors read around 500-600 according to base to colector and emiter and not on other direction. MOSFETS can retain their state because the Gate acts like capacitor and can charge and discharge Source - Drain conduction. You CAN'T test MOSFETS in diode test, you have to charge the gate and discharge it and measure it like switch (or potentiometer) who is controlled by the Gate. Resistors can go open or higher on resistance. Don't change 0.5 Ohms with 15 Ohms, those are current sense resistors, the device can go in current protection mode if you do that. Multicomponent tester that you have should test MOSFETS and show if they are within specs. You can damage MOSFET with static discharge. YOU HAVE TO CHECK ALL COMPONENTS BEFORE TURN IT ON. USE REGULAR LIGHT BULB IN SERIES WITH INPUT CABLES to prevent blowing the components in case of shorts.
When your brother asked if mosfets have "memory" or if they latch, yes they do, sort of. A "latch" device like an SCR will stay on until all power through the circuit drops below a certain threshold. Mosfets can certainly hold their state outside of circuit, basically by charging the gate. Remember the gate of a mosfet is similar to a capacitor and it holds a charge. For example applying a momentary positive voltage (with respect to the source) to the gate of an enhancement mode N channel mosfet will turn the mosfet on and it will stay on until the gate is discharged (typically by connecting the source to the gate).
Was gonna say a similar thing but also include that MOSFETS can kinda "latch-up" if not driven properly (i.e. the MOSFET gets stuck on/off and won't transition back, or, slowly transitions back to the previous state. Usually this is if the gate-charge isn't sourced and drained fast enough. Has this incident when modifying a SCR-triggered soldering station to run as a battery powered portable soldering station.... before the TS100 became a thing.)
When used in ac circuits like a dimmmer control this will turn off the SCR automatically when the device is reverse biased. A mosfet has a very high input impedance on the gate and that's why a small voltage fed through your bodies resistance to the gate will turn on the mosfet. Then that voltage gets removed again when you short it out with your fingers. Unlike a current controller device like a regular transistor, a mosfet works more like a tube/valve device that is voltage controlled.
An SCR/TRIAC will latch However, a mosfet would not, and these look like a push pull combo, n channel and p channel driving the promary side of the coil But yes, the gate has capacitance so the gate has to be pulled to ground to switch it off (or a resistor from ground)
Very well done to be someone that actually says there not hard up and that nothing will be put behind a pay-wall and only pay if they can comfortably. Appreciate the honesty also keep up the good videos 👍👍👍
A lot of inverters will make that squealing sound if the input voltage from the batteries fall below around 11.5 volts D.C. . check the input battery voltage before you connect the inverters and then once the inverter is on and see how much the battery voltage drops and if its below 11.5 volts or so that may be one of the reasons. Also the output transistors as well as the pwm mosfet driver ic often fails along with the input and out put transistors so you pretty well need an oscilloscope to see if there is an output from the driver ic. I love these type of switching power supply type of videos, please do more if possible.
I have a advice for you. Every time you want to power something for testing. Please use a bench powersupply with current limit function, it will protect the components on the device from blowing up. Inverters like these only require about 2amp to produce the required output voltage with no load , so by using a for testing you can safely test the device at low currents without having to use a big lead acid battery and shorting it out and harming it.
Handy knowledge there... Though, I ask for what current would a full sine inverter like the ones in APC SmartUPS systems? Just curious as I had reverse-wired the battery in the UPS (power cut the day I got the batteries, wired them under candle light, was a bad mistake ._. ).... I have a PSU that does 10A CC (but only trust it at 5A continuous CC), I guess that'd be enough? what's the likelyhood the battery-side is referenced live? (I not found schematics, but I guess that they'd design it isolated.... I know how to handle mains, just don't want to blow up a bench PSU atop the UPS) If ya don't know, sorry to bothered ya :)
@@itzzjok3rzz208 It didn't work on the inverter because he had the voltage set too low. Most inverters have low voltage dropout circuits and won't start on less than 12 volts.
Suggestion: When trying to fix "Blows-the-fuses" stuff, try replacing the fuses with an appropriate-voltage incandescent light bulb for test. The bulb will actively limit current to non-destructive levels and allow powered testing. I'd use a 12-volt auto headlamp for the inverter, for instance; and a 75-watt 220V(Europe) or 110V(US) for a small tube(valve) radio. A 50-watt lamp should be suitable for most line-powered solid-state stuff. Just wire the lamp in series with the line and use appropriate cautions of course. The lamp power should be about twice the power rating of the device under test. Good Luck and thanks for the excellent video series!
Car batteries are 12.5v+, even close to 13v fully charged. That thing probably thinks your "battery" is dead when you give it 11.96v with those thin wires
51:12 12V batteries measure about 13.8V when charged and 11.9V discharged so that inverter is reading undervoltage when you feeded it with the PSU. Check the voltage on that battery and you'll see.
5 amps will run a vacuum cleaner and microwave oven so 5 Amp is quite a bit. When I was a truck driver I had a full desktop computer with a CRT monitor that I ran on a 600 watt 120V power inverter.
This is my favorite, when your brother help you with fixing things you explain and talking about your fix in a really entertaining way! Love it thank you!
Check the 4 diodes nearest the mosfets I had same problem and two diodes was open both ways and I should say thank you as it was your video that give me the idea to check my mosfet I removed it and it was bad but still had a short them I check my diodes and two was open out of the 4 of them
your brother is right, the fuses would blow sooner as 25 amp rather than a 35 amp and 40 amp. as for the noise it is an indication of low battery current or voltage. I have had it happen on my inverter, and works fine after running the car engine for a few seconds, and letting the engine power take over, plus also after giving the car a run it works fine.
also why when replacing fuses in a plug you want the same or lower amp fuse, it is far safer to work your way up in fuses rather than work your way down, when not sure what fuse to replace it with. you just do it until it stops blowing fuses when you know a product is working fine.
Parasitically MOSFETs can sort of stay on for a short while as the gates are basically little capacitors, but most circuits have pulldown resistors to turn them off as a failsafe. Also touching the legs with your fingers will drain any charge from the gate, having said that charge on the gate won't stay there for long on its own due to leakage.
@@StezStixFix cheers bud, I was kinda shocked when he mentioned me, I looked at my stats and could see my subs increasing and thought wtf then I watched the video lol 😆
I would order a few bottles of "Magic Smoke" to replace that which you have let escape. 😂😂 Thanks for the entertaining video. Electronic repair is fun and often frustrating.
I think from memory the battery can supply 100A. Even if the inverter could switch on, it would only be outputting a theoretical maximum of 240V 0.5A with the power supply. However it would be lower than 0.5A due to the circuitry of the inverter using some power. On the battery a theoretical maximum of 5A could be outputted but again it will be lower than 5A because of the power the invertor circuitry uses. Looking at the label on the inverter it says 500W meaning it outputs just over 2A. That means the inverter needs just under 3A just to switch on or 6 times the current of what the power supply can deliver. As for the beeping I would suggest that you check the diodes and capacitors on the output stage for shorts and the resistors for being open. As the chip is testing for the voltage and current being right. Since it doesn't see what it is expecting to find it sends the signal to start the beep.
I always like to watch such a video. Although there is a failure in repair. It's a pity that I didn't have popcorn but only coffee to watch the video. I'm glad you have the Patreon. Of course I was waiting for it and I'm already a member. I hope this helps and I will have something to look at, learn and admire skills
Great vid Vince, To answer your question regarding the battery working but not the PSU. You might check the voltage drop on your PSU leads, they look rather thin, just measure the voltage on them while under load, so just hook up a 12v LED strip or something that is going to draw a farily decent amount and use your meter to measure the voltage on the croc clips,, alternatively you could measure the resitance of the leads and calculate the drop....I'd guess theyre dropping voltage, if this is the case you might want to put beefier wires on bannana and croc. It's also possible the battery is also at a higher voltage when fully charged and of course your battery leads are very chunky and unlikely to be dropping any significant voltage. I'll just add, when selecting mosfets, don't concern yourself with selecting the exact same, more often than not your absolutely fine putting in another make/brand provided the current and voltage rating matches or exceeds the max rating of the one your replacing, this is not always the case as there is more variables but in this instance it would be absolutely fine provided the pinout is the same
the blown mosfets are part of H matrix circuit which generates the output sin/modified-sin wave AC. The 4 mosfets should be of the same number and same patch, that's critical most of the time. In my estimation, the DC 12 to 240V DC is probably ok that can be measured with H-matrix mosfets not installed. BEWARE the hugh capacitors will be charged with 240V DC. Discharge them by connecting them to 240V lamp. If that part ok, then you can check the IC circuitry is pulsing the H-matrix transistors correctly. you'll need a scope for that. BTW try to put a 2.2ohm 10W resistor inline with the battery positive to avoid fire in case of a direct short. The last inverter is beeping because the output voltage didn't get up in time.
@22:00 MOSFETs can turn on with the test voltage from the meter, if you reverse polarity on the same pins you can turn them on/off sometimes and get different results. LOL @28:00 never mind, you figured it out.
Search for the datasheet of the DIP IC next to the optocouplers. That should be the controller for turning the high voltage DC to AC (it controls the 4 MOSFETS trough 2 of the optocouplers, the 3rd opto handles feedback). The datasheet should explain what gate driving signals to expect. Then you can try running the device without the MOSFETS installed (and thus without risking damage) and check the signals from IC all the way to the gates. There's probably still something wrong along the way causing shoot-trough.
A good tip if working with low voltage high current device is study ohm's law which will give some insight into resistance of conductors . The leads from your PSU are way to thin to carry the current the inverter needs. They have a high demand as it needs to charge the big caps up on startup. Have worked on many different inverter types and more than few that have gone bang. If you can get a circuit diagram of even just block diagram, but you probably won't get the exact model but one very similar will give some idea what things are and what to look for and where. Thanks for the video.
Also check the opto-isolators are all good. I have a feeling the switcher feedback is not working. The source of the original issue may be one of the capacitors, so check the smaller caps in the same area.
Interesting video - good video and audio. More determination than knowledge - you'll learn more as you delve !! I watched this because someone is trying to give me an inverter to fix.
You can use a light bulb in series with the fuse block while testing blown fuses. Instead of a fuse lighting, you will light the bulb with any excess current from a short.
You will need an old fashioned light bulb though, led or anything like that won't work. But yeah, I have an extension cord with a light bulb in between the cord to do testing like this...
@@patzik1910 You're correct and thank you for adding that. You can generally use 24 or 12 automobile bulbs for lower voltage stuff. You can also use 120v tungsten Christmas light bulbs that are coming back in to fashion again.
Have you tried the beeping one on a running car or a battery on a charger. I have one that isn't like "smart" per say but it will turn off if the voltage dips below 12. It would do the same thing where it would start beeping pretty quickly and wouldn't power the high voltage side.
My inverters alarms like that when the input voltage is too low you need to check the 12 volt battery when the red fault comes on it may be low less than about 11.2 volts because car batteries are around 12.6 volt when fully charged.
This one looks like it could be risky. Love the great work Vince. I've said it before I learn so much more from watching you learn than seeing an expert just running through something start to finish.
They are designed to run with the engine running or a fully charged battery same as Ham Radios they don't like to work below 12 volts and even that is a little low for some things. Mate keep up the good work I will give more likes since that is what I can do
Usually what blow the MOSFETs on inverters is a incorrect switching order because they need to alternate between each other to get AC, which means that if one fails to turn off (either because of a short or a incorrect gate potential) then when it alternates it will short out the others.
General rule of switching power supply troubleshooting is: If you have components failing on secondary side, look for a cause on primary side, and vice versa.
I've only got as far as the intro - for now! But one word describes your approach to Patreon - "classy." Great to hear the trying to fix videos are staying as I had thought they were going to disappear!
"What a Ride" 👍😎 Thank You - A "differential scope probe" would be a way to more safely troubleshoot a "switching" power supply. But I don't recommend it. 2 Pricey & Dicey IMHO ⚡🔥 🤤 Hey, those MOSFETS were kinda "latchy" in a way 🤔
Look up the beep codes for the device. All of my inverters alarm if the input voltage is too low. Other than that the onboard CPU is likely detecting a fault in the drive circuitry. No output means it is failing before output voltage is generated. You could put a meter on the output and see if the voltage tries to climb, what frequency it is at, etc.
Vince keep it up man always love your videos you certainly have a special way of doing videos which is just great and you have made me smile and laugh quite a few times too, also I always learn something from watching your videos the longer they are the better I say keep it up will be a sad day when there's no more myate Vince videos.
the 4 diodes which are the bridge rectifier need testing, pull them ALL out of circuit, test them then put them back and test as a bridge rectifier they are right next to the 4 blown mosfet, then text the red resistor thing and any ceramic caps out of circuit, check the diodes feeding the 2 yellow supplies, from memory these are the things that take out fuses and mosfets, after that it can only be the 2 big caps or the 2 yellow supplies, that being said im a noob not a trained pro
Watching video whilst commenting on my phone, subscribed to both guys as they have what looks like my favourite kind of content. Thanks Vince, on my last comment it autocorrected to Vincent, that was not intentional lol
When the Mosfets shorted it sent high voltage to the drive circuit damaging it. Also tell your brother to not overload the inverters (he seems have blown a few of them), if it says 600W then use max 300W max. The leads from your power supply will be dropping voltage at 10A, even though you have 12V at the power supply you may only get 9 or 10V at the input to the inverter. keep up the good work.
Vince, your power supply leads are very thin and you will not be supplying the 12 volts at the point they connect to the inverters cables. That inverter is going to need a good high current supply and steady 12-14v and those leads will be dropping voltage across them because they are so thin. Remember the 600w inverter requires approx 50amps to run at full power. Approx calculations 600W/250V=2.5 amps, Times that by the step up ratio 240V/12V=20 so 2.5A x 20 = 50amps at 12 volts. This is without taking the poor efficiency into consideration ! So your little 10amp power supply is only giving a fraction of the current and after the voltage drop in the thin leads, not enough voltage or current to power the inverter properly. The internal fan will work slower on the reduced voltage tho and you can hear it running slower than when connected to the battery. A car battery can supply in the region of hundreds of amps when it kicks over your cars starter motor for cranking your engine. Think about the size of leads your dealing with on a car and the inverter and compare to those silly thin test leads !! Also the in rush current of the inverter probably peaks above the output of the power supply and that will current limit the power supply but in this instance I'm surprised your thin leads don't melt or get hot at least, just like how a fuse works!! Lol.
Hey guys, buy a 12v 20-50watt incandescent bulb ( in a holder ) and place that in series with the 12v battery If it fuses, the light will come on, but it would limit the current to the inverter preventing bangs
Hint for next time . Big a$$ bulb in the battery / psu feed when testing . If one FET is faulty check the gate resistors & diodes / clamping diodes . Chang all the fet's don't test & refit . Fit just one 10 or15 amp fuse for the smoke test .
@@StezStixFix haha yeah it's really nice of vince, the fact he shouts out and shows appreciation for his subscribers is amazing. I already had just over 4k but should be hitting 5k pretty soon thanks to him. I like how he pointed out your channel too because we all know how hard those first 1k subs are so to say he's just given you the opportunity to start earning is really nice 👌
@@StezStixFix absolutely, he's the only person I ever gave money to on patreon too lol. I donate to Rossmann sometimes on stream but other than that I generally don't donate or sign up to paid subscriptions lol
My Mate Vince, If the Donor Inverter fails after you replace the borrowed Mosfets, the failure is due to a miss match of the two replacement Mosfets being either slightly faster or slower, this mismatch is caused by environmental changes, along with impurities within the materials from one batch to another batch of production. Having said that and if the Original Inverters Mosfets are cheap, I would replace all of them, as I suspect this may be the reason why an eventual failure occurred, This miss match has caused one or two mosfets having to do most of the work thus stressing them to their failure, and once they failed, what we had was a cascade of failures ergo taking out one extra Mosfet. If you decide to replace all of them, I would suggest before you power it on, you first check all Diodes, also check that socketed IC for shorts to it's ground pin, if there is a short replace it "The IC" and check components around the IC empty socket for incorrect values to resistors, Resistors should have resistance, if they're open then they need to be replaced, as should any short circuited capacitors be replaced.. GOOD LUCK..
Great video =D Shame they couldn't all be repaired. When you knocked something over at 49:40 it scared the s*** out of me lol! Regards that test at the end - car batteries provide 50 / 100 / more amps etc. 10 amps from a bench PSU just isn't enough.
GadgetUK164 - Retro Gaming Repairs & Mods ... yes I was thinking 10amps might be the minimum needed. Come on Vince add some additional meters for in-circuit current and voltage. I’ve come across optimistic lab supplies which say “...is was 12v when it left us mate...” but don’t truly reflect the voltage under load.
Hey Vince, I have a smaller one of these that run off a lighter socket. Mine beeps the same until I start the car so I suspect it's insufficient input voltage
I would just cut my losses and rebuild the inverter around a ROYER oscillator like a push pull oscillator but a feedback coil across the two bases of the two transistors and a single bias resistor of 47K to VCC plus a 470pf capacitor across the two collectors so as to get a nice clean sine wave, it is a shame you cannot use Sanken MOSFET power transistors, I would replace the MOSFETS as well as the driver chip in each of the inverters.
That beeping sound you hear might be anything to be honest but start with a freshly charged battery because it has higher voltage than 12v, 12volts on 6cell lead acid battery is almost flat (11.8 with no load on battery is 0%) and fully charged is around 13v. These inverters pull a ton of current when turning on and if they detect low voltage they shut off to protect the battery because it doesnt know if the battery is really low or if it cannot deliver sufficient current. Im no professional by any means but I've been around electronics all my life and this could be the problem imo
@@simontay4851 Eh? "A ton" is a bit of an expression... I think pretty much anyone can guess that they aren't referring to the unit "ton". I don't see an need to be pedantic here.
With the final issue, running from the bench supply. Check the current draw with a clamp meter, or simply put a 10A fuse in line and see if it blows. I would think if you are attempting to draw more than 10A the bench supply will complain, or the voltage will start to drop. Check the voltage on the scope. I suspect the voltage will have a lot of ripple, which may upset the inverter.
I was about to say the same thing but read your post, I was also going to advise Our Mate Vince to order 4 "Matched Mosfets" as in they all come from the same production batch or even better all from the same date of production for the Borrowed Inverters return to operation..
@@KorAllRBare Yes. All the MOSFETs need to be same, as at high voltage side these 4 MOSFETs are used in a H-Bridge configuration can slight difference can lead to failures. Would suggest to try to power the inverter without those 4 MOSFETs and theb if everything is fine (Test that the MOSFETs pin on board for 230+ dc voltage). Also while testing doesn't need to put all the fuse just one fuse should work.
@@sam_8a 🐨Yep, I'm Quite aware of how Mosfets share the work load "Current", and I agree with your recommendations, Another method mentioned elsewhere is Current limited voltage injection at key points, which requires one to understand each section of a given circuit and it's prime component and what each supporting component it is required to do for it along with what the section of the circuits intended function is, it would also help to have a schematic of the device, especially when the device originates from China.. 🤣 ?! 🤓
Hey My mate vince idk if you've done this yet but you should make a how to Port Forward tutorial I know its different for every router but it would still be a video someone can learn from
Vince, about time put up a way to support you! But mate, put it in link and/or pinned first comment. Just the link is enough if that's all you want. You can bulk modify comments and descriptions using Tube Buddy to add it to all you're videos.
This is a boosting switch mode power supply that runs on 12V and outputs approx 300VDC. The 240VAC is created by fast switching the 4 mosfets or groups of mosfets in an H-bridge. Some filtering, smoothing and safety is added. And that's it.
To repair: Remove the mosfets. Check them. If one is damaged, order new ones from the same batch for all positions of that section. They should be balanced. Now first, clean up burnt areas, resolve shorts, replace parts that are obviously broken, check small transistors, check the gate resistors, and all other small stuff. If you have one, then connect a 2-channel oscilloscope to the gate connections of both mosfet groups and power up the device using a current-limited 13V supply. You should briefly see nice drive signals, just before the protection powers the thing down again. Turn it off. If you don't have a scope, you can use a good AC multimeter that does not show DC components when measuring AC. Check that by measuring a DC voltage in AC setting. It must show almost 0V. So, at the gate connections you should see an AC voltage, indicating that there is a drive signal. If that is all working, for both mosfet groups, then we can proceed. Now, at each group, you mount one mosfet, so you blow up max 2 mosfets during testing. Connect a small test load and a multimeter to the main capacitors at the secundary side of the transformer: at the main capacitors. Test load can be the two of your smallest 240V incandescent light bulbs in series. Stand back and power up again, briefly. Your test lights should light, and your meter should indicate a significant DC voltage in the capacitors. If not, try again and take attention to your power supply. It might get overloaded by this. In that case, you'll need to use a bigger power supply or a battery. when using a battery, then use a smaller fuse while testing: 10Amps. So... You can proceed with checking drive signals at the high-voltage part. During this, you leave the light bulbs connected. They will discharge the capacitors fast, between every test you do. For safety. Here we do the same: before actually mounting mosfets, we first measure if drive signals are present at the gates. When all good, you can also mount some mosfets at the secondary stage. Connect another small incandescent light bulb to the output and test again.
When you ordered your mosfets from China, you should test them before mounting them. If all good, remove the test mosfets and mount all new mosfets. At this point, test again. If all good, remove your test light bulb, reassemble, install the correct fuse(s), test again with a battery and a bigger load.
These units can fail with a lot of damage. A mosfet usually fails into a short circuit. That kills the mosfet at the other side, too, probably in a short circuit as well. So now your 12V supply is short circuited. Hopefully, the fuse goes out before the tracks burn off the circuit board. Failing mosfets will often feed quite a lot of current into the drive circuitry, killing that off as well. So, if you just change the mosfets, you're setting yourself up for some more dead mosfets.
If your brother uses power tools on these units, you might want to add some more filtering to the output. Add a capacitor of the type you find in those fake power-saving plugs.
Thank you for reading until the end.
Good tips there but people shouldn't be buying semiconductors from china. They're all fakes, rebadged or rejects that have been rebranded with anyone's guess as to what they really are.
The process should go -> fuses -> transistors -> diodes ->caps -> resistors -> ic. The cracked component is optron (opto couple probably PC817). Check for shorts on all of the parts and then check for improper open, bulgy caps, diodes should show something only on one side. You can't change zener with diode, those are two different components. Diodes are fast recovery so they should read 150-400, transistors read around 500-600 according to base to colector and emiter and not on other direction. MOSFETS can retain their state because the Gate acts like capacitor and can charge and discharge Source - Drain conduction. You CAN'T test MOSFETS in diode test, you have to charge the gate and discharge it and measure it like switch (or potentiometer) who is controlled by the Gate. Resistors can go open or higher on resistance. Don't change 0.5 Ohms with 15 Ohms, those are current sense resistors, the device can go in current protection mode if you do that. Multicomponent tester that you have should test MOSFETS and show if they are within specs. You can damage MOSFET with static discharge. YOU HAVE TO CHECK ALL COMPONENTS BEFORE TURN IT ON. USE REGULAR LIGHT BULB IN SERIES WITH INPUT CABLES to prevent blowing the components in case of shorts.
When your brother asked if mosfets have "memory" or if they latch, yes they do, sort of. A "latch" device like an SCR will stay on until all power through the circuit drops below a certain threshold. Mosfets can certainly hold their state outside of circuit, basically by charging the gate. Remember the gate of a mosfet is similar to a capacitor and it holds a charge. For example applying a momentary positive voltage (with respect to the source) to the gate of an enhancement mode N channel mosfet will turn the mosfet on and it will stay on until the gate is discharged (typically by connecting the source to the gate).
The benefit of watching the video not when it just came out is that instead of writing a long comment I can simply like yours :)
Was gonna say a similar thing but also include that MOSFETS can kinda "latch-up" if not driven properly (i.e. the MOSFET gets stuck on/off and won't transition back, or, slowly transitions back to the previous state. Usually this is if the gate-charge isn't sourced and drained fast enough. Has this incident when modifying a SCR-triggered soldering station to run as a battery powered portable soldering station.... before the TS100 became a thing.)
When used in ac circuits like a dimmmer control this will turn off the SCR automatically when the device is reverse biased. A mosfet has a very high input impedance on the gate and that's why a small voltage fed through your bodies resistance to the gate will turn on the mosfet. Then that voltage gets removed again when you short it out with your fingers. Unlike a current controller device like a regular transistor, a mosfet works more like a tube/valve device that is voltage controlled.
An SCR/TRIAC will latch
However, a mosfet would not, and these look like a push pull combo, n channel and p channel driving the promary side of the coil
But yes, the gate has capacitance so the gate has to be pulled to ground to switch it off (or a resistor from ground)
Thank god trying to fix is still going to be around, these are the best videos
Very well done to be someone that actually says there not hard up and that nothing will be put behind a pay-wall and only pay if they can comfortably. Appreciate the honesty also keep up the good videos 👍👍👍
A lot of inverters will make that squealing sound if the input voltage from the batteries fall below around 11.5 volts D.C. . check the input battery voltage before you connect the inverters and then once the inverter is on and see how much the battery voltage drops and if its below 11.5 volts or so that may be one of the reasons. Also the output transistors as well as the pwm mosfet driver ic often fails along with the input and out put transistors so you pretty well need an oscilloscope to see if there is an output from the driver ic. I love these type of switching power supply type of videos, please do more if possible.
I've had a few car batteries go flat with these things. This beep, to me, says "you're bump-starting your car on this campsite" 😬All fun and games...
And measure the B+ volts at the inverter terminals, not the battery. you can loose up to a volt in under spec wires.
I have a advice for you. Every time you want to power something for testing. Please use a bench powersupply with current limit function, it will protect the components on the device from blowing up. Inverters like these only require about 2amp to produce the required output voltage with no load , so by using a for testing you can safely test the device at low currents without having to use a big lead acid battery and shorting it out and harming it.
he does but it doesnt for whatever reason work on those inverters
Handy knowledge there... Though, I ask for what current would a full sine inverter like the ones in APC SmartUPS systems?
Just curious as I had reverse-wired the battery in the UPS (power cut the day I got the batteries, wired them under candle light, was a bad mistake ._. ).... I have a PSU that does 10A CC (but only trust it at 5A continuous CC), I guess that'd be enough?
what's the likelyhood the battery-side is referenced live? (I not found schematics, but I guess that they'd design it isolated.... I know how to handle mains, just don't want to blow up a bench PSU atop the UPS)
If ya don't know, sorry to bothered ya :)
Set your power supply to 2.5A CC that should be enough to get the ups at it’s required output of course with no load
@@itzzjok3rzz208 It didn't work on the inverter because he had the voltage set too low. Most inverters have low voltage dropout circuits and won't start on less than 12 volts.
Suggestion: When trying to fix "Blows-the-fuses" stuff, try replacing the fuses with an appropriate-voltage incandescent light bulb for test. The bulb will actively limit current to non-destructive levels and allow powered testing. I'd use a 12-volt auto headlamp for the inverter, for instance; and a 75-watt 220V(Europe) or 110V(US) for a small tube(valve) radio. A 50-watt lamp should be suitable for most line-powered solid-state stuff. Just wire the lamp in series with the line and use appropriate cautions of course. The lamp power should be about twice the power rating of the device under test. Good Luck and thanks for the excellent video series!
That's a great and valuable suggestion. A guideline for everyone.
Patreon plug....very honest representation of your situation....nice to hear....good for you
Car batteries are 12.5v+, even close to 13v fully charged. That thing probably thinks your "battery" is dead when you give it 11.96v with those thin wires
yep, and once the engine and alternator are on, the voltage is 13.8v to 14.4v
Without a load on inverter there shouldn't be much voltage drop, also most of these kind of inverters have low voltage cut of 10.5v
@@sam_8a There will be an in rush current that probably exceeds the output from that PSU.
I surely admired your endurance towards fixing a thing. No many human has that quality. Looking forward for more such video. Keep it up.
51:12 12V batteries measure about 13.8V when charged and 11.9V discharged so that inverter is reading undervoltage when you feeded it with the PSU. Check the voltage on that battery and you'll see.
I admire your sheer tenacity and patience.
Having a blown apart opto-coupler is certainly a bad sign... you made the right choice there to do the shorted unit.
At least we got green lights. Very nice. I think they are very hard to fix but it was very entertaining. Thanks.
5 amps will run a vacuum cleaner and microwave oven so 5 Amp is quite a bit. When I was a truck driver I had a full desktop computer with a CRT monitor that I ran on a 600 watt 120V power inverter.
This is my favorite, when your brother help you with fixing things you explain and talking about your fix in a really entertaining way! Love it thank you!
Check the 4 diodes nearest the mosfets I had same problem and two diodes was open both ways and I should say thank you as it was your video that give me the idea to check my mosfet I removed it and it was bad but still had a short them I check my diodes and two was open out of the 4 of them
TO-220 package FETs will ALWAYS be G-D-S from left to right if I'm not mistaken, so no need to check that every time
your brother is right, the fuses would blow sooner as 25 amp rather than a 35 amp and 40 amp. as for the noise it is an indication of low battery current or voltage. I have had it happen on my inverter, and works fine after running the car engine for a few seconds, and letting the engine power take over, plus also after giving the car a run it works fine.
also why when replacing fuses in a plug you want the same or lower amp fuse, it is far safer to work your way up in fuses rather than work your way down, when not sure what fuse to replace it with. you just do it until it stops blowing fuses when you know a product is working fine.
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Parasitically MOSFETs can sort of stay on for a short while as the gates are basically little capacitors, but most circuits have pulldown resistors to turn them off as a failsafe. Also touching the legs with your fingers will drain any charge from the gate, having said that charge on the gate won't stay there for long on its own due to leakage.
Really interesting. Looking forward to the revisit! P.S. Thank you so much for the mention, Vince. 👍 I'm heading over to Patreon now to support you.
I subbed to you buddy you got some interesting content there :)
@@TheCod3r Thanks mate, likewise. I've just subbed to you!
@@StezStixFix cheers bud, I was kinda shocked when he mentioned me, I looked at my stats and could see my subs increasing and thought wtf then I watched the video lol 😆
@@TheCod3r Exactly the same here! 😅
@@TheCod3r 🛠️🧰⚙️🔧
Vince Optoisolators are two diodes. One to produce the light, the other to receive the signal back. You can test them on diode test.
I would order a few bottles of "Magic Smoke" to replace that which you have let escape. 😂😂 Thanks for the entertaining video. Electronic repair is fun and often frustrating.
I think from memory the battery can supply 100A. Even if the inverter could switch on, it would only be outputting a theoretical maximum of 240V 0.5A with the power supply. However it would be lower than 0.5A due to the circuitry of the inverter using some power. On the battery a theoretical maximum of 5A could be outputted but again it will be lower than 5A because of the power the invertor circuitry uses. Looking at the label on the inverter it says 500W meaning it outputs just over 2A. That means the inverter needs just under 3A just to switch on or 6 times the current of what the power supply can deliver. As for the beeping I would suggest that you check the diodes and capacitors on the output stage for shorts and the resistors for being open. As the chip is testing for the voltage and current being right. Since it doesn't see what it is expecting to find it sends the signal to start the beep.
proud to be throwing some change your way Vince, hope it helps!!
I always like to watch such a video. Although there is a failure in repair. It's a pity that I didn't have popcorn but only coffee to watch the video. I'm glad you have the Patreon. Of course I was waiting for it and I'm already a member. I hope this helps and I will have something to look at, learn and admire skills
Sooo happy to hear your finally on Patreon! Love your videos and can't wait to support you and your efforts! Thank you for videos Vince!!!
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@@BuckedDuckRarity end 2020 🛠️🧰🛠️🧰⚙️🔧⚙️🛠️🧰⚙️🔧🔧
I love when you get your brother involved and included!
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🛠️🧰⚙️🔧🛠️🧰⚙️🔧¿2021?
Love your honesty.
Great vid Vince, To answer your question regarding the battery working but not the PSU. You might check the voltage drop on your PSU leads, they look rather thin, just measure the voltage on them while under load, so just hook up a 12v LED strip or something that is going to draw a farily decent amount and use your meter to measure the voltage on the croc clips,, alternatively you could measure the resitance of the leads and calculate the drop....I'd guess theyre dropping voltage, if this is the case you might want to put beefier wires on bannana and croc. It's also possible the battery is also at a higher voltage when fully charged and of course your battery leads are very chunky and unlikely to be dropping any significant voltage. I'll just add, when selecting mosfets, don't concern yourself with selecting the exact same, more often than not your absolutely fine putting in another make/brand provided the current and voltage rating matches or exceeds the max rating of the one your replacing, this is not always the case as there is more variables but in this instance it would be absolutely fine provided the pinout is the same
the blown mosfets are part of H matrix circuit which generates the output sin/modified-sin wave AC. The 4 mosfets should be of the same number and same patch, that's critical most of the time. In my estimation, the DC 12 to 240V DC is probably ok that can be measured with H-matrix mosfets not installed. BEWARE the hugh capacitors will be charged with 240V DC. Discharge them by connecting them to 240V lamp. If that part ok, then you can check the IC circuitry is pulsing the H-matrix transistors correctly. you'll need a scope for that. BTW try to put a 2.2ohm 10W resistor inline with the battery positive to avoid fire in case of a direct short. The last inverter is beeping because the output voltage didn't get up in time.
@22:00 MOSFETs can turn on with the test voltage from the meter, if you reverse polarity on the same pins you can turn them on/off sometimes and get different results. LOL @28:00 never mind, you figured it out.
Search for the datasheet of the DIP IC next to the optocouplers. That should be the controller for turning the high voltage DC to AC (it controls the 4 MOSFETS trough 2 of the optocouplers, the 3rd opto handles feedback). The datasheet should explain what gate driving signals to expect. Then you can try running the device without the MOSFETS installed (and thus without risking damage) and check the signals from IC all the way to the gates. There's probably still something wrong along the way causing shoot-trough.
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A good tip if working with low voltage high current device is study ohm's law which will give some insight into resistance of conductors . The leads from your PSU are way to thin to carry the current the inverter needs. They have a high demand as it needs to charge the big caps up on startup. Have worked on many different inverter types and more than few that have gone bang. If you can get a circuit diagram of even just block diagram, but you probably won't get the exact model but one very similar will give some idea what things are and what to look for and where. Thanks for the video.
Also check the opto-isolators are all good. I have a feeling the switcher feedback is not working. The source of the original issue may be one of the capacitors, so check the smaller caps in the same area.
I felt bad so I didn’t skip the beginning I hope u can do 2 vids a week
I'm just glad Vince is still around uploading quality content.
Interesting video - good video and audio.
More determination than knowledge - you'll learn more as you delve !!
I watched this because someone is trying to give me an inverter to fix.
You can use a light bulb in series with the fuse block while testing blown fuses. Instead of a fuse lighting, you will light the bulb with any excess current from a short.
You will need an old fashioned light bulb though, led or anything like that won't work. But yeah, I have an extension cord with a light bulb in between the cord to do testing like this...
@@patzik1910 You're correct and thank you for adding that. You can generally use 24 or 12 automobile bulbs for lower voltage stuff. You can also use 120v tungsten Christmas light bulbs that are coming back in to fashion again.
You are seriously a good dude. Keep up the good work.
Thank you.
Nikkai Maplins very own brand and not surprised it's no longer working 🛠️🧰⚙️🔧
Next video Vince fixes the world with a bodge wire and a couple of fuses.
transistors have Base Emitter Collector, MOSFETs have Gate Sorce Drain
Watching the ads all the way through to help Vince
22:00 Correct. They do not retain their state, they're like basic switches (very simplified) in that context
Have you tried the beeping one on a running car or a battery on a charger. I have one that isn't like "smart" per say but it will turn off if the voltage dips below 12. It would do the same thing where it would start beeping pretty quickly and wouldn't power the high voltage side.
My inverters alarms like that when the input voltage is too low you need to check the 12 volt battery when the red fault comes on it may be low less than about 11.2 volts because car batteries are around 12.6 volt when fully charged.
Much appreciated regardless of outcome..
This one looks like it could be risky. Love the great work Vince. I've said it before I learn so much more from watching you learn than seeing an expert just running through something start to finish.
this comment is to help the algorithm for the my mate vince`s channel .. love ya work vince
click his playlist and let it run over night, i do it on my pc everyday
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Welldone vince . Honestly is come first. That why i love you videos. God bless you
1st class video to watch thank you take care kind regards from me kenneth
They are designed to run with the engine running or a fully charged battery same as Ham Radios they don't like to work below 12 volts and even that is a little low for some things. Mate keep up the good work I will give more likes since that is what I can do
Glad to see a patreon I get paid soon I'll be sure to support :D
Usually what blow the MOSFETs on inverters is a incorrect switching order because they need to alternate between each other to get AC, which means that if one fails to turn off (either because of a short or a incorrect gate potential) then when it alternates it will short out the others.
@Windows98GamerYT 🛠️🧰⚙️🔧 End 2020
Sounds like a low power noise from battery. It makes a noise so you don’t run battery down
General rule of switching power supply troubleshooting is: If you have components failing on secondary side, look for a cause on primary side, and vice versa.
I've only got as far as the intro - for now! But one word describes your approach to Patreon - "classy." Great to hear the trying to fix videos are staying as I had thought they were going to disappear!
End 2020 🎉🎊🎆🎇
the minute his Patreon pops up... I signed up :) hope everyone else is too!
That beep is a low voltage alarm or try replacing the chips
This is what is known as "shotgunning components" at the fix, and its perfectly acceptable to me.
Regarding the socketed IC being unusual for a new product - mate, the whole thing is through-hole! However new a product it is, it is an old design.
"What a Ride" 👍😎 Thank You
- A "differential scope probe" would be a way to more safely troubleshoot a "switching" power supply. But I don't recommend it. 2 Pricey & Dicey IMHO ⚡🔥 🤤
Hey, those MOSFETS were kinda "latchy" in a way 🤔
Look up the beep codes for the device. All of my inverters alarm if the input voltage is too low. Other than that the onboard CPU is likely detecting a fault in the drive circuitry. No output means it is failing before output voltage is generated. You could put a meter on the output and see if the voltage tries to climb, what frequency it is at, etc.
Vince keep it up man always love your videos you certainly have a special way of doing videos which is just great and you have made me smile and laugh quite a few times too, also I always learn something from watching your videos the longer they are the better I say keep it up will be a sad day when there's no more myate Vince videos.
the 4 diodes which are the bridge rectifier need testing, pull them ALL out of circuit, test them then put them back and test as a bridge rectifier they are right next to the 4 blown mosfet, then text the red resistor thing and any ceramic caps out of circuit, check the diodes feeding the 2 yellow supplies, from memory these are the things that take out fuses and mosfets, after that it can only be the 2 big caps or the 2 yellow supplies, that being said im a noob not a trained pro
At 12:00 mins, the transistor near to the big smoothing caps is also had the arse blown out of it
To test you wouldn't need to put all three fuses in, just installing one of them would reduce the chance of it blowing up good parts.
Smaller inverters is like the one better thing about the American electric system
Watching video whilst commenting on my phone, subscribed to both guys as they have what looks like my favourite kind of content. Thanks Vince, on my last comment it autocorrected to Vincent, that was not intentional lol
When the Mosfets shorted it sent high voltage to the drive circuit damaging it. Also tell your brother to not overload the inverters (he seems have blown a few of them), if it says 600W then use max 300W max. The leads from your power supply will be dropping voltage at 10A, even though you have 12V at the power supply you may only get 9 or 10V at the input to the inverter. keep up the good work.
Power Inverters 12V to 230V 🛠️🧰⚙️🔧
Great video vince so nice for you to be very honest and not doing a paywall ：）
hi Vince. excellent video. One question: can you hear the screaming from the viewers? please dont stop you are genuine and very entertaining. Good job
Oh well....it's a TRYING to fix, you never promised it would be a fix 😁👍🇩🇰
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End 2020 🛠️🧰⚙️🔧
Love your trying to fix videos videos.
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Vince, your power supply leads are very thin and you will not be supplying the 12 volts at the point they connect to the inverters cables. That inverter is going to need a good high current supply and steady 12-14v and those leads will be dropping voltage across them because they are so thin. Remember the 600w inverter requires approx 50amps to run at full power. Approx calculations 600W/250V=2.5 amps, Times that by the step up ratio 240V/12V=20 so 2.5A x 20 = 50amps at 12 volts. This is without taking the poor efficiency into consideration !
So your little 10amp power supply is only giving a fraction of the current and after the voltage drop in the thin leads, not enough voltage or current to power the inverter properly. The internal fan will work slower on the reduced voltage tho and you can hear it running slower than when connected to the battery. A car battery can supply in the region of hundreds of amps when it kicks over your cars starter motor for cranking your engine. Think about the size of leads your dealing with on a car and the inverter and compare to those silly thin test leads !! Also the in rush current of the inverter probably peaks above the output of the power supply and that will current limit the power supply but in this instance I'm surprised your thin leads don't melt or get hot at least, just like how a fuse works!! Lol.
Did you ever check the bridge rectifier on the high voltage side as if any of the diods there failed it could take out the Transistors.
Hey guys, buy a 12v 20-50watt incandescent bulb ( in a holder ) and place that in series with the 12v battery
If it fuses, the light will come on, but it would limit the current to the inverter preventing bangs
Hint for next time .
Big a$$ bulb in the battery / psu feed when testing .
If one FET is faulty check the gate resistors & diodes / clamping diodes .
Chang all the fet's don't test & refit .
Fit just one 10 or15 amp fuse for the smoke test .
Thank you for the shout out by the way thats amazing 👏 💜
@Windows Gamer thank you buddy much appreciated
Amazing isn't it? I was genuinely shaking watching Vince's video when we appeared on the screen! 😅
@@StezStixFix haha yeah it's really nice of vince, the fact he shouts out and shows appreciation for his subscribers is amazing. I already had just over 4k but should be hitting 5k pretty soon thanks to him. I like how he pointed out your channel too because we all know how hard those first 1k subs are so to say he's just given you the opportunity to start earning is really nice 👌
@@TheCod3r Yep, he's such a genuinely nice guy, you can tell! This is why we all love Vince.
@@StezStixFix absolutely, he's the only person I ever gave money to on patreon too lol. I donate to Rossmann sometimes on stream but other than that I generally don't donate or sign up to paid subscriptions lol
You should definitely buy a transistor tester. It will save a lot of your time on testing.
My Mate Vince, If the Donor Inverter fails after you replace the borrowed Mosfets, the failure is due to a miss match of the two replacement Mosfets being either slightly faster or slower, this mismatch is caused by environmental changes, along with impurities within the materials from one batch to another batch of production.
Having said that and if the Original Inverters Mosfets are cheap, I would replace all of them, as I suspect this may be the reason why an eventual failure occurred, This miss match has caused one or two mosfets having to do most of the work thus stressing them to their failure, and once they failed, what we had was a cascade of failures ergo taking out one extra Mosfet.
If you decide to replace all of them, I would suggest before you power it on, you first check all Diodes, also check that socketed IC for shorts to it's ground pin, if there is a short replace it "The IC" and check components around the IC empty socket for incorrect values to resistors, Resistors should have resistance, if they're open then they need to be replaced, as should any short circuited capacitors be replaced.. GOOD LUCK..
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My Mate Vince 2021 🛠️🧰🛠️🧰⚙️🔧⚙️🔧
Great video =D Shame they couldn't all be repaired. When you knocked something over at 49:40 it scared the s*** out of me lol! Regards that test at the end - car batteries provide 50 / 100 / more amps etc. 10 amps from a bench PSU just isn't enough.
GadgetUK164 - Retro Gaming Repairs & Mods ... yes I was thinking 10amps might be the minimum needed. Come on Vince add some additional meters for in-circuit current and voltage. I’ve come across optimistic lab supplies which say “...is was 12v when it left us mate...” but don’t truly reflect the voltage under load.
Haha, I did exactly the same! I was watching with my headphones on and it made me jump out of my skin! 😆
The cables from that PSU look pretty skimpy - there could have been a very significant voltage drop along the cables...
Really enjoying videos vince 🙂
Hey Vince, I have a smaller one of these that run off a lighter socket. Mine beeps the same until I start the car so I suspect it's insufficient input voltage
@44:00 have you checked all the Schottky diodes ?
It's very common for MOSFETs to blow in order to protect the fuse.
LOL
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@@krzbrew end 2020 🛠️🧰⚙️🔧
When you connect the inverter to the car battery shouldn't you connect the Red lead first then the Black one? I was told that's safer
I would just cut my losses and rebuild the inverter around a ROYER oscillator like a push pull oscillator but a feedback coil across the two bases of the two transistors and a single bias resistor of 47K to VCC plus a 470pf capacitor across the two collectors so as to get a nice clean sine wave, it is a shame you cannot use Sanken MOSFET power transistors, I would replace the MOSFETS as well as the driver chip in each of the inverters.
A 12V car battery should be between 12.6V and 13.2V fully charged. I wonder if you fully charge the battery if you would get different results
I got my Patreon membership with you.
end 2020 'Trying to FIX' series. Many thanks, Vince.
That beeping sound you hear might be anything to be honest but start with a freshly charged battery because it has higher voltage than 12v, 12volts on 6cell lead acid battery is almost flat (11.8 with no load on battery is 0%) and fully charged is around 13v.
These inverters pull a ton of current when turning on and if they detect low voltage they shut off to protect the battery because it doesnt know if the battery is really low or if it cannot deliver sufficient current.
Im no professional by any means but I've been around electronics all my life and this could be the problem imo
They pull A LOT of current. Not ton.
@@simontay4851 Eh? "A ton" is a bit of an expression... I think pretty much anyone can guess that they aren't referring to the unit "ton". I don't see an need to be pedantic here.
With the final issue, running from the bench supply. Check the current draw with a clamp meter, or simply put a 10A fuse in line and see if it blows. I would think if you are attempting to draw more than 10A the bench supply will complain, or the voltage will start to drop. Check the voltage on the scope. I suspect the voltage will have a lot of ripple, which may upset the inverter.
Gotta love that he's trying to mix up his videos and make different types of content i respect that.
Congrats, you repaired the LED...
Power them up in series with a car head light if there's a short it will light up and protect the inverter
All 4 output MOSFETs must be same, else a slightly different characteristics can lead to short
I was about to say the same thing but read your post, I was also going to advise Our Mate Vince to order 4 "Matched Mosfets" as in they all come from the same production batch or even better all from the same date of production for the Borrowed Inverters return to operation..
@@KorAllRBare Yes. All the MOSFETs need to be same, as at high voltage side these 4 MOSFETs are used in a H-Bridge configuration can slight difference can lead to failures. Would suggest to try to power the inverter without those 4 MOSFETs and theb if everything is fine (Test that the MOSFETs pin on board for 230+ dc voltage). Also while testing doesn't need to put all the fuse just one fuse should work.
@@sam_8a 🐨Yep, I'm Quite aware of how Mosfets share the work load "Current", and I agree with your recommendations,
Another method mentioned elsewhere is Current limited voltage injection at key points, which requires one to understand each section of a given circuit and it's prime component and what each supporting component it is required to do for it along with what the section of the circuits intended function is, it would also help to have a schematic of the device, especially when the device originates from China.. 🤣 ?! 🤓
Hey My mate vince idk if you've done this yet but you should make a how to Port Forward tutorial I know its different for every router but it would still be a video someone can learn from
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Vince, about time put up a way to support you!
But mate, put it in link and/or pinned first comment. Just the link is enough if that's all you want. You can bulk modify comments and descriptions using Tube Buddy to add it to all you're videos.
I think that is a low battery voltage alarm.