I recently started getting back into electronics repair after 35 years of not doing anything with it. Things have changed in 35 years, and now I'm learning all over again. I decided to get back into it because my wife collects animated Christmas toys. Most of them she finds at second hand shops, so they don't work most of the time. Your channel is a great channel to watch because of the detail you show in troubleshooting the circuit. It helps me a great deal. Cheers!
@@BuyitFixit The second hand stores are a great place to look for broken items. I have even found items that would be worth a little money due to their age. Good luck.
I found your channel a few weeks ago. you do impressive work. I used to repair CRT TV's 30 odd years ago as a hobby and now my hands shake so much it would be dangerous if i tried. Keep up the good work.
The Zig X-70 are a very well engineered unit. After years of life in a caravan, often with a damp atmosphere, some corrosion is inevitable. Should give many more years of service now.
Hi I have a grundig satellit 3400 radio no power .would like too see it working again. Think this would make a good video and would pay for carriage and repair Many thanks desi
13.8v is the voltage of a fully charged lead-acid battery with no load. 14.3v is the recommended minimum voltage for charging a lead-acid battery. Automotive alternators generally output around 14.7v to 15v or so. Since this is a charger, 14.3v is to be expected at the output. When connected to a battery, the device MAY be designed to monitor the voltage and current to adjust the output up or down to go from charging to standby/float voltage and current.
I think it just has output set to 14,3V, this will not boil battery and could be left charging whole weekend. Also charging current is limited and measured by that shunt as completely depleted battery would otherwise take too much current.
I think that ancient single stage charger was not worth fixing. Nobody uses a wet lead acid battery in a caravan (or certainly should never do so to avoid explosions) Not sure what sort of amps this unit can charge at, but a modern 15 or 25 amp Li capable charger is affordable AND multi-stage for AGM/GEL/SLA batteries which are safe to use in a van.
i use my zig to charge a golf cart battery that runs my diessel heater. its still very usefull. also everybody uses wet lead acid in caravans. we aint all rich@@einfelder8262
The first thing I noticed when you removed the case was that the mains earth cable connected to the PCB rather than directly to the metal case, and at the end that had suffered corrosion presumably from being damp for a prolonged period. Even if there was an intended earthing path at the adjacent mounting screw, that path could be compromised. The appropriate earthing technique nowdays would be for the earth cable to terminate directly to one side of the case, with a link to the other half of the case, and also to the PCB if required, that way all elemants of the case are directly earthed, and not dependant on screws and nuts for earthing integrety.
Great detective work as usual. All the way through I'm thinking he's going to swap the big vertical resistor, (that's turned the board brown,) for something with a higher wattage.
Thanks 👍I wasn't too sure on the original value. It did show some resistance, and when I searched online most of the baords I came across looked exactly the same.
I just fixed an Enermax PSU that had failed output caps and apparently it didn't like having those caps bad so it blew a diode. Looks like when a cap fails takes out some components with them in SMPSs.
Was the diode noticeable or did you DMM test each one? I had a cap on a refrigerator board blow, replacing the cap didnt fix it. No obvious damage and the diodes checked out. Bought new but now relooking at the old board to see if I can post mortem it with yours and Buyitfixit's help.
Switched modes are tough without a schematic. Sometimes, a crap shoot. One thing I always tell myself troubleshooting these.. they need 4 things to operate, start, run, regulate and shutdown. I always start looking for the initial start pulse somewhere, usually the regulator chip. It may only be there initially, it should remain high from a feedback from the main chopper winding or secondary winding on the primary.
Good job of seeing it through to completion. The big, burned resistor should be replaced; its pin is totally corroded. You might do well to make yourself a DIY Capacitor "Stinger." They are very handy for discharging caps. Search RUclips for designs. Mostly, you need a high value/high wattage resistor, two bamboo chop sticks, a piece of wire, two header pins and heat shrink. HTH.
Thanks 👍I cleaned up the resistor pads and turned it round the other way to the resistor body keeps the loose pad in place. I was unsure of the value and don't have the schematic so I was unsure of what value it was supposed to be. I've seen those home built resistors capacitor discharges before, I've just not got round to building one. Thanks for the suggestion 👍
Howdy again sir! I mention a power supply, you fix something not so dissimilar! 😂 I also picked up that La Metric from Amazon, currently reduced so why not. Did also catch this video last night, as it's a military operation to change my bed, so I thought whilst watching...!
6:20 Dont think you needed to take the power transistor bolts out they had clearance holes in the case . I always try least disassembly as pos , love your videos handy to have heads up on similar fixes.
Yes, you don't need to remove them unless replacing the transistors or diodes. I didn't realise until I realised you had to drill the rivets out to get it out of the case.
Another great fix, Mick...impressive Maybe a quick general inspection under the microscope could've helped you spotting those damaged components since they were too small.
Connect a series lamp, if the input circuit is good the lamp will draw power for a short second and it will turn off, if thats the case its the output part of the circuit which has the problem, if the lamp is on the entire time its the input circuit. It saves a bit of time doing this so u dont waste time figuring out which part of the board is at fault
That was a Marathon effort, well done. Maye not cost effective if you factor your time in, but you enjoy fixing stuff and have learned stuff about another item. Looking forward to your next one already 🙂
HI, I started my career and a TV engineer in the 70's (Rumbelows UK) when Valves were a thing and progress to thru to full solid-state TV and then computers,. You remind me of me many years ago and love your persistence. I always used to say take a close visual evaluation first and then note what is working as much as what is not! I had an apprentice Paul who had much potential who moved up to the Nort east. Anyway good job and what microscope are you using? Great stuff and keep it up. PS you can find may short circuit faults by injecting a regulated high current source into a faulty circuit and use your thermal camera.
Thanks 👍Yes I remember Rumbelows 🙂 The microscope is an Trinocular Amscope clone on a boom arm with a 48MP camera and two 0.5x Barlow lenses. Yes I used voltage injection a few times, like on the Crucial SSD I repaired on here a couple of months back 🙂
Very nice video thank you. Did you re-check the voltage on the chip after you replaced the zener to see if it changed from the 7v vcc and the 4.8 Vref you measured before?
Thanks 👍 Good job you asked, as I must have forgot to switch it off last night at 2AM, and it's been on all day. At least it's had a good soak test now 😂😂😂 I just pulled the top off again and checked. VCC to the chip is now 23.8V and Vref is 5.024V.
That was so interesting. During the pandemic I dragged out about a dozen of old caravan chargers that I had replaced when I worked as a mobile service technician ( brakes, gas, road lights etc.) . Some faults were visually obvious and when I replaced the part/s I did the same using an old 55w head lamp bulb as a load test for half an hour but I don't have enough electronic knowledge to understand which component played what part down to the level you can. Merry Xmas.
Hi, I'm also a volonteer at the local repair cafe since 10 years and watching your channel for quite some time. I admire your perseverence and 'never give up attitude'. Some criticism though: If you do things off camera that doesn't feel right to the viewers as they do not see what's going on. Imo it devaluates your channel. Do your repairs on camera and just show what you are doing, that's genuine ! Cheers!
Thanks, the only issue is that you sometimes can't put everything in a video otherwise it would be too long. I spent a fair bit of time on this on and off, so I would have probably had about 4 or 5 hours of footage. I think the main parts of what I did were in there, thanks for the advice.
Excellent fix!! Id bet the difference in output voltages is due to a battery maintenance ( float, desulfate, etc) circuit. I think you’d find that after it’s been connected to the coach’s battery bank for a while you’d see varying voltages as the state of charge increases. That being said, a bad coach battery(ies) could be to blame for the shore charger failing to begin with. Great video!! I look forward to the next. BTW… Do you have an outlet (eBay, etc)where you sell items you repair ?
Hi, I expected you to look at the input switching transistors differentially on your scope, mostly because many new people don't know how and why its done. Nice video, some things are illusive especially when you don't have a schematic.
Great determination to reach a conclusion, Curious as to what the zener voltage was. I just know that one day we'll see a dim bulb tester (or fire extinguisher for increased viewing figures).
Yes, he needs a true VAC power system... Mains wall plug to all stop emergency switch to isolation transformer to autotransformer (Variac) to dim bulb current limiter to DUT. All of it, including the isolation transformer, can be DIY;d, except for the autotransformer. Do not buy an Asian autotransformer, as they have lots of safety problems and grossly overstate their ratings. Buy a name brand unit. All that said, switch mode power supplies, such as this one, may not run on an autotransformer. I suggested a cap stinger, in a separate comment.
Another awesome and well detailed video! I've got thermal camera on the way as a Christmas present from the wife, I'm sure I'll be looking at some really stupid things on Christmas day, just for fun. What voltages were coming out of the chip for the scope? Not got funds for a real scope just yet. I've setup a Raspberry Pi Pico W with the open source Scoppy project, the pins are only 3.3v tolerant so I'll need to make some voltage dividers.
Thanks Dave, I can't remember the voltage, but one of the waveforms was about half the height of the other. I think I was on the collector of the transistors on the bottom of the board when I measured it off camera.
At this age of electronics it's better to assume all electrolytic capacitors are dried out partially. To give the board another lifespan I would just replace all of them without thinking long. Goes much quicker and is still cheaper than checking considering the saved work hours.
I do remember measuring it, but perhaps that bit never made it onto the video. I wasn't sure of the correct value of it though as all of the markings had burnt off if I remember.
I'm not sure what the value of the resistor is supposed to be, and there were no obvious markings on it. It did still have resistance. When I was looking at pictures of other units they all appear to look the same (discoloured and burnt) so I think it's a design "feature".
I'm not sure what it does, I didn't work that part of the circuit out. It seems that the pictures of other units on the internet all look the same. I swapped the resistor round so the loose pad cant move now.
I thought these testers were able to test capacitors in-circuit (because they work at low voltage and don't activate PN junctions or something like that, that's beyond my understanding). Have you tried it?
@@NicksStuff Yes, ESR meter often gives good indication when testing an electrolytic capacitor in circuit. An ESR meter simply measures resistance to a low voltage AC current (roughly 1 volt at something like 50-100 kHz AC, depends on the meter). The ESR the meter is reading (in ohms) is just an indicator, its not supposed to be an empirical measurement. Theoretically, an electrolytic should have zero resistance to AC current, in practice it just needs to be low (esr close to zero). If there is a resistor in parallel with the near zero esr of a capacitor, the resistor will have negligible effect on the esr mesasurement, the only exception being when the resistor has lower ohms than the capacitor esr. In this case you will be measuring the lower resistance of the resistor (because the capacitor has high esr). This is only a problem if the parallel resistor is only a few ohms or less (becasue it gives you false reading of low esr, when the capacitor is actually shot). But usually the parallel resistor is more than a few ohms, so you will still suspect high esr in the capacitor. Hope that make sense. edit. What this means is that you can routinely flip a board over and quickly check esr of all of the electrolytic capacitors in circuit, identify any that may be suspect. Dodgy ones usually stand out like a sore thumb, low value capacitors of a few uF are a bit tricky, they often have a few ohms esr when perfectly fine (measure some brand new ones to confirm, its a good way to "calibrate" and get to know your esr meter). I have a 1ohm resistor glued to my esr meter, I use it to check the meter is still working properly.
I hate SMPS I struggle to get invested in them so I would have grown to hate it over the days and it would hate me but more and then I would despise it then bin it ! Glad you got the scope out thats one thing I check on these buggers then grotty caps, some have a 431 reference that can go south. I think thats the thing with 'um they die from so many different problems...anyways job's a good un...cheers.
I think the supply probably lost regulation as those electrolytics slowly died causing the output to exceed 15V and the zener sacrificed itself as designed to shut the output down. Those switch mode supplies can be a nightmare to fault find and typically use less than top quality electrolytics. Well tracked down.
well done mick on fixing the Zig x-70 I have a similar zig x-70 that's damaged, I can see the choke LF2 in the heatshrink is damaged and trips the mains. Would you have any idea what value it is ? thanks
Thanks for reply Mick, I think myself that its not too critical as there is 2 chokes wound round common core for noise suppression on the ac L and N lines , I might try one I got out of old microwave to see will it do the job mike @@BuyitFixit
Hi if you dont mind me asking where is your local repair cafe? It sounds an interesting place that i would like to check out (im a fellow electronics repair engineer in the Tyneside area). I am of course making assumptions from your accent.
It may be because we haven't got all of the equipment I have at home. There are just some things that aren't possible to do at our repair cafe currently.
Hi, when I first started doing videos I used an old iPhone 6, which did an OK job but I couldn't zoom in and out (so I had to do that in the editing software using digital zoom). I now use a used Sony HDR-CX450 with a third party wired remote. You can get a 4k version too, but I just went for the HD model. I've got it mounted on an overhead boom arm with a 4ft LED batten light that I used for lighting. Hope that helps 👍
Very long shot here but wondering if you happen to remember the value of R48 on this board. The larger 2 or 3w grey one down near the outputs (Where the boards scorched). Ive inherited one and this seems to be missing :(
Really sorry, I can't remember off hand. I did measure it and it did show a resistance at the time which I assumed was correct. I think it was somewhere around 1K or so, but I could be totally wrong!
@@BuyitFixit No worries, I knew it was a bit of a long shot :) I found that the lower its resistance, the lower the output voltage. Your guess may be correct as Ive found I can get 14.2v on the output using a 1.1K. Sadly I think im missing something else as the output evaporates under load. Ill keep plugging away, thanks for getting back to me.
@@BuyitFixit its a bench power supply not sure if its hantek or something. It just wouldn't turn on one day then when i tried again it did then intermitant. Now off altogether no lights nothing.
@@davidiley529 interesting drop me an email if you like. It's on the channel about page under for business enquiries. It doesn't show on a phone or tablet for some reason.
I was just wondering if I would be able to send you a PSU that's failed for you to have a look at? I'm a fire alarm engineer and any one in the trade will tell you how bad the Gent Vigilon psu's are at dying leaving site without a working fire alarm. It would be of interest to see if I could get them working again so I can swap them out there and then. Cheers thanks.
Hi there, I have a 48v samsung lithium pack for an e scooter that had been allowed to discharge beyond the BMS safe point. I've individually slowly recharged each of the 13 paralleled cell packs to make them even and get them to 3.5v each the BMS still won't allow me to charge via it. But it appears to have a rechargeable cell and presumably a memory and quite possibly needs a reset of some kind. I've tried shorting P to B of BMS but with no success. Can you please help?
It depends on the protection IC. I'd start by looking for chip numbers and then searching for data sheets. I had similar with a ring doorbell. The chip seemed to be non resettable.
You mean the one at 23:13 I guess - pause it there and you can see that it's labelled Multi-Function Tester T7 - a quick google will reveal that it's an LCR T7. RUclips has assorted videos on them.
Sorry Mick. I have a satire ish sense of humour. I apologize to both yourself and Vince if my humour seemed slightly abstract . Unreservedly sorry for any confusion sustained .
LM358 is a jelly bean part, there is no excuse for not recognising it from the first milisecond you saw it! And because the damn current transformer is right next to it, an 358 does measure from ground, ofcourse it's part of the current loop ( you need no degree to know that, it's basic electronics ). On the other hand measuring the mains bridge is pointless since the fuse is ok, also the power transistors must be ok just because the fuse is fine... I've seen this channel recommended on eevblog forum by someone, but i see it's a waste of time, there is no substitute for electronics theory, and that you do not have unfortunately...
Sorry if it's not up to your level of expertise. I don't profess to be an electronics expert, and that's not the purpose of the channel. I'm just a guy that fixes stuff and a fair few different things (the idea is to help people with similar broken items repair theirs). Remember someone else may have one with a faulty bridge and now they know how to test it. I've fixed a wide variety of stuff from Thermal cameras, a medical ultrasound scanner (which I also unlocked ton of hidden features and ran DOOM on) to solar inverters where I even had to reverse engineer their software and write my own service tool which I made available free to download to help others. No, I don't know everything, and I do make mistakes.
@@BuyitFixit ok, maybe i was a bit harsh, so sorry for that. It's just that in all i do regarding electronics engineering i strongly promote electronics theory because i believe it is the only way to evolve in a better version of yourself. And LM358 it is by far the most popular opamp out there ( that is why it's called a "jellybean part" ), it's one of those opamps used just about everywhere by everyone, and every electronics person knows it... On the other hand, sorry if i have to be somewhat rough again, but if someone does not know hot to measure a bridge rectifier then someone should stay far, FAR away from line powered switching supplies, they really kill those that do not know what their doing. I guess i can relate to what you are trying to do, so good luck, maybe ill stick around. Happy holidays!
![Seungmin "그렇게, 천천히, 우리(As we are)" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/kAzmhLHePqU/mqdefault.jpg)
My mate Vince would've plugged it in from the room next door with a pair of Wellies and Marigold rubber gloves on with a plastic bucket on his head.
😂😂😂😂
and a broom handle to flick the switch 😁😁
😂😂😂
I actually like Vince. He's a decent bloke. I've spoken to him quite a few times over comments and on emails...
Better be safe than sorry but Vince is a great guy too and a pretty good fixer too
I recently started getting back into electronics repair after 35 years of not doing anything with it. Things have changed in 35 years, and now I'm learning all over again. I decided to get back into it because my wife collects animated Christmas toys. Most of them she finds at second hand shops, so they don't work most of the time. Your channel is a great channel to watch because of the detail you show in troubleshooting the circuit. It helps me a great deal. Cheers!
Thanks 👍I had been thinking of getting something like that to do over Christmas but I haven't got anything as yet.
@@BuyitFixit The second hand stores are a great place to look for broken items. I have even found items that would be worth a little money due to their age. Good luck.
I started playing with furbies, got two non workers for 50p.
I found your channel a few weeks ago. you do impressive work. I used to repair CRT TV's 30 odd years ago as a hobby and now my hands shake so much it would be dangerous if i tried. Keep up the good work.
Thank you, sorry to hear about your hands 🙁. I too used to fix the odd CTR too, I remember changing frame ICs and line output transistors 👍
The Zig X-70 are a very well engineered unit. After years of life in a caravan, often with a damp atmosphere, some corrosion is inevitable. Should give many more years of service now.
Thanks Andy 👍
Hi I have a grundig satellit 3400 radio no power .would like too see it working again. Think this would make a good video and would pay for carriage and repair
Many thanks desi
13.8v is the voltage of a fully charged lead-acid battery with no load.
14.3v is the recommended minimum voltage for charging a lead-acid battery.
Automotive alternators generally output around 14.7v to 15v or so.
Since this is a charger, 14.3v is to be expected at the output.
When connected to a battery, the device MAY be designed to monitor the voltage and current to adjust the output up or down to go from charging to standby/float voltage and current.
Thanks for that ED! Much appreciated 👍
I think it just has output set to 14,3V, this will not boil battery and could be left charging whole weekend. Also charging current is limited and measured by that shunt as completely depleted battery would otherwise take too much current.
I think that ancient single stage charger was not worth fixing. Nobody uses a wet lead acid battery in a caravan (or certainly should never do so to avoid explosions) Not sure what sort of amps this unit can charge at, but a modern 15 or 25 amp Li capable charger is affordable AND multi-stage for AGM/GEL/SLA batteries which are safe to use in a van.
i use my zig to charge a golf cart battery that runs my diessel heater. its still very usefull. also everybody uses wet lead acid in caravans. we aint all rich@@einfelder8262
Great job, big sigh of relief when it powered up with no buzzing 👍👏👏
Thanks 👍
I love the sound of the toothbrush at 10x speed. It's like a power scrubbing tool 😂
😂😂😂😂👍
Great perseverance on this one Mick. Well done!
Thanks Vince 👍
After a while starring at the board it's easy to miss a diode. Great job. Look forward to the next one.
Thanks, yes I spent ages scratching my head with this one 😂😂😂
Seek and ye shall find. No better way to put it. Pure Genius. Thank you for such a great video.
Thanks Fred 👍
Fair play to you for not quitting when most would have 😁
Thanks 👍I think the award for not quitting probably belongs to my latest video of the AVerMedia device I just looked at 😂😂😂
The first thing I noticed when you removed the case was that the mains earth cable connected to the PCB rather than directly to the metal case, and at the end that had suffered corrosion presumably from being damp for a prolonged period. Even if there was an intended earthing path at the adjacent mounting screw, that path could be compromised. The appropriate earthing technique nowdays would be for the earth cable to terminate directly to one side of the case, with a link to the other half of the case, and also to the PCB if required, that way all elemants of the case are directly earthed, and not dependant on screws and nuts for earthing integrety.
Good point 👍
Great detective work as usual. All the way through I'm thinking he's going to swap the big vertical resistor, (that's turned the board brown,) for something with a higher wattage.
Thanks 👍I wasn't too sure on the original value. It did show some resistance, and when I searched online most of the baords I came across looked exactly the same.
your videos so enjoyable because of your intelligence its very enjoyable
Thank you 🙂Much appreciated👍
You have a good patience. And have knowledge that I wish I had.
Thanks Peter 👍
I just fixed an Enermax PSU that had failed output caps and apparently it didn't like having those caps bad so it blew a diode. Looks like when a cap fails takes out some components with them in SMPSs.
Nice 👍Yes, agree.
Was the diode noticeable or did you DMM test each one? I had a cap on a refrigerator board blow, replacing the cap didnt fix it. No obvious damage and the diodes checked out. Bought new but now relooking at the old board to see if I can post mortem it with yours and Buyitfixit's help.
BRAVO! nice see you stay with and not launch it out of the window!!! Great diagnosis.
Thanks, yes took a little bit of tracking down that one 😂👍
Switched modes are tough without a schematic. Sometimes, a crap shoot. One thing I always tell myself troubleshooting these.. they need 4 things to operate, start, run, regulate and shutdown. I always start looking for the initial start pulse somewhere, usually the regulator chip. It may only be there initially, it should remain high from a feedback from the main chopper winding or secondary winding on the primary.
Yes, and thanks 👍
Great patience and methodical fault finding. I hate throwing things away..
Thank you 👍
Lovely video once again.....I love Saturday evening
Thanks 👍 Glad you enjoyed it 🙂
Heya, oh wouw that pcb looks dirty. a nice and complicated repair with multipol fault well done
Been looking forward to a new video nice cuppa and relax thanks for sharing mate 👍
And thank you too for watching 👍🙂
Good job of seeing it through to completion. The big, burned resistor should be replaced; its pin is totally corroded. You might do well to make yourself a DIY Capacitor "Stinger." They are very handy for discharging caps. Search RUclips for designs. Mostly, you need a high value/high wattage resistor, two bamboo chop sticks, a piece of wire, two header pins and heat shrink. HTH.
Thanks 👍I cleaned up the resistor pads and turned it round the other way to the resistor body keeps the loose pad in place. I was unsure of the value and don't have the schematic so I was unsure of what value it was supposed to be. I've seen those home built resistors capacitor discharges before, I've just not got round to building one. Thanks for the suggestion 👍
Howdy again sir! I mention a power supply, you fix something not so dissimilar! 😂
I also picked up that La Metric from Amazon, currently reduced so why not.
Did also catch this video last night, as it's a military operation to change my bed, so I thought whilst watching...!
😂😂👍
I repaired one of these the other week..turned out it was one of the output caps that had gone..just replaced it and it started working
Nice 👍I was searching for the company website but it seems they went out of business some years ago...
Reminds me of when I tried and failed to fix the power supply unit for a large mixing desk. Excellent work!
Thanks! 👍
Very satisfying. Persistence and skill pay off again.
Thanks 👍🙂
your patience and tenacity are exceptional, i learn a lot; THKS
My pleasure👍
Awesome channel my friend.
Thank you kindly👍🙂
6:20 Dont think you needed to take the power transistor bolts out they had clearance holes in the case . I always try least disassembly as pos , love your videos handy to have heads up on similar fixes.
Yes, you don't need to remove them unless replacing the transistors or diodes. I didn't realise until I realised you had to drill the rivets out to get it out of the case.
The first thing i noticed was that brown area around that large resistor, danger will robinson.....
Just seen the end, well done.
Thanks 🙂👍
That was supper troubleshooting skills. Well done.👌👌
Thanks 👍
Another great fix, Mick...impressive
Maybe a quick general inspection under the microscope could've helped you spotting those damaged components since they were too small.
Cheers mate 👍
Connect a series lamp, if the input circuit is good the lamp will draw power for a short second and it will turn off, if thats the case its the output part of the circuit which has the problem, if the lamp is on the entire time its the input circuit. It saves a bit of time doing this so u dont waste time figuring out which part of the board is at fault
Thanks for the tip 👍
Top stuff Mick, well done again. 🙂
Thanks 👍
You can go higher on voltage with capacitors if you don’t have an exact match just not lower. As long as the capacitance is the same.
Yes agree. I've done that a few times, although it also depends if space allows, as usually higher voltage capacitors have a larger footprint 👍
great fix as usual, thanks Mick 😀
Thanks Mike 👍
Really enjoy your methodical approach to repair. Talking through your thoughts really helps us learners!
Thanks 👍Glad you are finding them useful 🙂
That was a Marathon effort, well done. Maye not cost effective if you factor your time in, but you enjoy fixing stuff and have learned stuff about another item. Looking forward to your next one already 🙂
Thanks Chris 👍
More patience than me, mate. Well done!
Cheers Steve 👍
The repair cafe is such a cool concept. Thank you for sharing your time and talent with your community!
My pleasure!
I'm surprised to see you're not on Odysee yet like EEVBLOG and most other electronics channels!
I might have a look into that. Thanks 👍
05:07 it sounds like closing a old door 🤣🤣
41:55🥳🥳 finaly measuremts with the dso 👍👍
Good work and repair, another one rescued 🍻🍻
😂😂😂at old door. Thanks👍, yes this one had me scratching my head for a while, but I eventually figured it out 🙂
Beautiful and impressive job!!! Thank you so much for your videos. Have a great week end!!!
Thanks 👍hope you have a great weekend too!
HI, I started my career and a TV engineer in the 70's (Rumbelows UK) when Valves were a thing and progress to thru to full solid-state TV and then computers,. You remind me of me many years ago and love your persistence. I always used to say take a close visual evaluation first and then note what is working as much as what is not! I had an apprentice Paul who had much potential who moved up to the Nort east. Anyway good job and what microscope are you using? Great stuff and keep it up. PS you can find may short circuit faults by injecting a regulated high current source into a faulty circuit and use your thermal camera.
Thanks 👍Yes I remember Rumbelows 🙂 The microscope is an Trinocular Amscope clone on a boom arm with a 48MP camera and two 0.5x Barlow lenses. Yes I used voltage injection a few times, like on the Crucial SSD I repaired on here a couple of months back 🙂
Very nice video thank you. Did you re-check the voltage on the chip after you replaced the zener to see if it changed from the 7v vcc and the 4.8 Vref you measured before?
Thanks 👍 Good job you asked, as I must have forgot to switch it off last night at 2AM, and it's been on all day. At least it's had a good soak test now 😂😂😂 I just pulled the top off again and checked. VCC to the chip is now 23.8V and Vref is 5.024V.
@@BuyitFixit Nice 🙂
That was so interesting. During the pandemic I dragged out about a dozen of old caravan chargers that I had replaced when I worked as a mobile service technician ( brakes, gas, road lights etc.) . Some faults were visually obvious and when I replaced the part/s I did the same using an old 55w head lamp bulb as a load test for half an hour but I don't have enough electronic knowledge to understand which component played what part down to the level you can. Merry Xmas.
Thanks 👍and Merry Christmas to you too!
Hi, I'm also a volonteer at the local repair cafe since 10 years and watching your channel for quite some time. I admire your perseverence and 'never give up attitude'. Some criticism though: If you do things off camera that doesn't feel right to the viewers as they do not see what's going on. Imo it devaluates your channel. Do your repairs on camera and just show what you are doing, that's genuine ! Cheers!
Thanks, the only issue is that you sometimes can't put everything in a video otherwise it would be too long. I spent a fair bit of time on this on and off, so I would have probably had about 4 or 5 hours of footage. I think the main parts of what I did were in there, thanks for the advice.
Excellent fix!! Id bet the difference in output voltages is due to a battery maintenance ( float, desulfate, etc) circuit. I think you’d find that after it’s been connected to the coach’s battery bank for a while you’d see varying voltages as the state of charge increases. That being said, a bad coach battery(ies) could be to blame for the shore charger failing to begin with. Great video!! I look forward to the next.
BTW… Do you have an outlet (eBay, etc)where you sell items you repair ?
Thanks 👍a lot of the stuff I repair I either keep or still have lying around 😂😂I need to have a clear out.
Hi, I expected you to look at the input switching transistors differentially on your scope, mostly because many new people don't know how and why its done.
Nice video, some things are illusive especially when you don't have a schematic.
Thanks 👍🙂
Mick another amazing repair, we always know it’s going to work 😊
Thanks for sharing !
Thanks mate 🖕
Great determination to reach a conclusion, Curious as to what the zener voltage was. I just know that one day we'll see a dim bulb tester (or fire extinguisher for increased viewing figures).
😂😂😂😂👍
Yes, he needs a true VAC power system... Mains wall plug to all stop emergency switch to isolation transformer to autotransformer (Variac) to dim bulb current limiter to DUT. All of it, including the isolation transformer, can be DIY;d, except for the autotransformer. Do not buy an Asian autotransformer, as they have lots of safety problems and grossly overstate their ratings. Buy a name brand unit. All that said, switch mode power supplies, such as this one, may not run on an autotransformer. I suggested a cap stinger, in a separate comment.
This channel is awesome 👍
Thanks 👍🙂
Another awesome and well detailed video!
I've got thermal camera on the way as a Christmas present from the wife, I'm sure I'll be looking at some really stupid things on Christmas day, just for fun.
What voltages were coming out of the chip for the scope?
Not got funds for a real scope just yet. I've setup a Raspberry Pi Pico W with the open source Scoppy project, the pins are only 3.3v tolerant so I'll need to make some voltage dividers.
Thanks Dave, I can't remember the voltage, but one of the waveforms was about half the height of the other. I think I was on the collector of the transistors on the bottom of the board when I measured it off camera.
At this age of electronics it's better to assume all electrolytic capacitors are dried out partially. To give the board another lifespan I would just replace all of them without thinking long. Goes much quicker and is still cheaper than checking considering the saved work hours.
Good advice, although it may depend on the amount of capacitors involved?
Good advice, although it may depend on the amount of capacitors involved?
Nicely done, again!
Thank you 👍
Very nice and professional content. Thank you...
So nice of you🙂Thanks 👍
Did you say that that brown glue becomes conductive? On JVC? That's good to know.
Yes, search "conductive glue carnage" 🙂
I wonder why you never looked at the resistor on the left side that was black and had the skid mark on the board?
I do remember measuring it, but perhaps that bit never made it onto the video. I wasn't sure of the correct value of it though as all of the markings had burnt off if I remember.
Great job.
Cheers 👍
Sleuth master! Nice.
Thanks 👍🙂
never saw the burned resistor fixed. did i miss something.
I'm not sure what the value of the resistor is supposed to be, and there were no obvious markings on it. It did still have resistance. When I was looking at pictures of other units they all appear to look the same (discoloured and burnt) so I think it's a design "feature".
What about that toasty high power resistor near the output? The traces seemed fried. Is that the dummy load?
I'm not sure what it does, I didn't work that part of the circuit out. It seems that the pictures of other units on the internet all look the same. I swapped the resistor round so the loose pad cant move now.
Excellent, very satisfying! 🙂
Thank you! 😊
You gotta discharge the caps first before putting them in the tester .
Good point. I think they would have discharged by the time I de-soldered them bit I guess I should have checked 👍
With regards to the heat damage around the resistor, is this normal?
I've seen pictures of a few of these, and they all seem to have that scorched resistor...They probably should have had a higher wattage one perhaps.
he did more realistic repairing job..isnt He?
please push like button below 😅
Thanks 👍
I thought these testers were able to test capacitors in-circuit (because they work at low voltage and don't activate PN junctions or something like that, that's beyond my understanding). Have you tried it?
No, not tried that but if there are other components such as a resistor in parallel with the capacitor I can't see it working correctly.
@@BuyitFixitThe resistors in parallel would generally be quite large and mostly on the high voltage capacitors, wouldn't they?
@@NicksStuff Yes, ESR meter often gives good indication when testing an electrolytic capacitor in circuit.
An ESR meter simply measures resistance to a low voltage AC current (roughly 1 volt at something like 50-100 kHz AC, depends on the meter). The ESR the meter is reading (in ohms) is just an indicator, its not supposed to be an empirical measurement. Theoretically, an electrolytic should have zero resistance to AC current, in practice it just needs to be low (esr close to zero). If there is a resistor in parallel with the near zero esr of a capacitor, the resistor will have negligible effect on the esr mesasurement, the only exception being when the resistor has lower ohms than the capacitor esr. In this case you will be measuring the lower resistance of the resistor (because the capacitor has high esr). This is only a problem if the parallel resistor is only a few ohms or less (becasue it gives you false reading of low esr, when the capacitor is actually shot). But usually the parallel resistor is more than a few ohms, so you will still suspect high esr in the capacitor. Hope that make sense.
edit. What this means is that you can routinely flip a board over and quickly check esr of all of the electrolytic capacitors in circuit, identify any that may be suspect. Dodgy ones usually stand out like a sore thumb, low value capacitors of a few uF are a bit tricky, they often have a few ohms esr when perfectly fine (measure some brand new ones to confirm, its a good way to "calibrate" and get to know your esr meter). I have a 1ohm resistor glued to my esr meter, I use it to check the meter is still working properly.
@@jumboegg5845 Thanks!
I hate SMPS I struggle to get invested in them so I would have grown to hate it over the days and it would hate me but more and then I would despise it then bin it ! Glad you got the scope out thats one thing I check on these buggers then grotty caps, some have a 431 reference that can go south. I think thats the thing with 'um they die from so many different problems...anyways job's a good un...cheers.
Cheers AndyMouse 👍
The heatsink on these are often conected to the mains , so no touchy
The heatsink is the directly connected to the outside case... would make for a bit of a dangerous power supply 😂
I think the supply probably lost regulation as those electrolytics slowly died causing the output to exceed 15V and the zener sacrificed itself as designed to shut the output down. Those switch mode supplies can be a nightmare to fault find and typically use less than top quality electrolytics. Well tracked down.
Thanks Ian 👍
Good find, thanks for sharing
Thanks John 👍
Nice video, did you replace with the original chip
Thanks 👍I tried both, both work.
Great job as always
Thanks 👍🙂
well done mick on fixing the Zig x-70
I have a similar zig x-70 that's damaged, I can see the choke LF2 in the heatshrink is damaged and trips the mains.
Would you have any idea what value it is ? thanks
Thanks mate. Unfortunately not, and I can't measure it as I gave it back to it's owner. Sorry.
Thanks for reply Mick, I think myself that its not too critical as there is 2 chokes wound round common core for noise suppression on the ac L and N lines , I might try one I got out of old microwave to see will it do the job
mike @@BuyitFixit
@@MichaelODywer yes or from an old ATX PSU
Where do you think the noise was coming from and how it went away when you changed the diode?Great fix 👍
Thanks 👍I think it was noise from the transformer not being switching properly. It went away when the switching circuit was working correctly.
Hi if you dont mind me asking where is your local repair cafe? It sounds an interesting place that i would like to check out (im a fellow electronics repair engineer in the Tyneside area). I am of course making assumptions from your accent.
Hi, I'm over in Cumbria now and Alston is the nearest one to me. They are dotted all over the world! www.repaircafe.org/en
I work in a Repair Cafe too, but we are asked not to take things home or outside the events they organize.
It may be because we haven't got all of the equipment I have at home. There are just some things that aren't possible to do at our repair cafe currently.
Hi what camera do you use to take these vidios
Hi, when I first started doing videos I used an old iPhone 6, which did an OK job but I couldn't zoom in and out (so I had to do that in the editing software using digital zoom).
I now use a used Sony HDR-CX450 with a third party wired remote. You can get a 4k version too, but I just went for the HD model. I've got it mounted on an overhead boom arm with a 4ft LED batten light that I used for lighting.
Hope that helps 👍
Very long shot here but wondering if you happen to remember the value of R48 on this board. The larger 2 or 3w grey one down near the outputs (Where the boards scorched). Ive inherited one and this seems to be missing :(
Really sorry, I can't remember off hand. I did measure it and it did show a resistance at the time which I assumed was correct. I think it was somewhere around 1K or so, but I could be totally wrong!
@@BuyitFixit No worries, I knew it was a bit of a long shot :)
I found that the lower its resistance, the lower the output voltage. Your guess may be correct as Ive found I can get 14.2v on the output using a 1.1K. Sadly I think im missing something else as the output evaporates under load. Ill keep plugging away, thanks for getting back to me.
My money was on a capacitor. I thought for sure the noise was a capacitor sizzling.
Yes, it does sound a little bit like that.
Those pop rivets are really an indication that power supply was never designed to be serviced.
Yes seems that way. They were no match for my drill though 😂😂😂
I wish i could get my power supply fixed but thers nobody near Bedlington that does repairs.
What is it mate? Was that the ATX one? Sorry it's hard to keep track with so many comments across different videos.
@@BuyitFixit its a bench power supply not sure if its hantek or something. It just wouldn't turn on one day then when i tried again it did then intermitant. Now off altogether no lights nothing.
@@davidiley529 interesting drop me an email if you like. It's on the channel about page under for business enquiries. It doesn't show on a phone or tablet for some reason.
@@BuyitFixit i'll check exactly what make it is tomorrow and get back to you. Thankyou
@davidiley529 No problem 👍
I was just wondering if I would be able to send you a PSU that's failed for you to have a look at? I'm a fire alarm engineer and any one in the trade will tell you how bad the Gent Vigilon psu's are at dying leaving site without a working fire alarm. It would be of interest to see if I could get them working again so I can swap them out there and then. Cheers thanks.
Drop me an email it's on the channel about page under for business enquiries.
@@BuyitFixit ok thanks I've done that.
Hi there, I have a 48v samsung lithium pack for an e scooter that had been allowed to discharge beyond the BMS safe point. I've individually slowly recharged each of the 13 paralleled cell packs to make them even and get them to 3.5v each the BMS still won't allow me to charge via it. But it appears to have a rechargeable cell and presumably a memory and quite possibly needs a reset of some kind. I've tried shorting P to B of BMS but with no success. Can you please help?
It depends on the protection IC. I'd start by looking for chip numbers and then searching for data sheets. I had similar with a ring doorbell. The chip seemed to be non resettable.
@@BuyitFixit can I send you a couple of pics and let me know what you think please?
Hi bit random but what is the tester called not the multi meter
You mean the one at 23:13 I guess - pause it there and you can see that it's labelled Multi-Function Tester T7 - a quick google will reveal that it's an LCR T7. RUclips has assorted videos on them.
I put links in the video description 👍
Where can i get the discord server info?
discord server?
Did anyone also say to themselves watch you're eyes the light is coming back on like in big clives videos
😂😂😂😂👍
How can we get hold of u by email or Facebook my son has done a logo and intro for u lol he loves your videos
There's an email address on the channel about page. You have to press the button for business enquiries. It only shows on PC or laptop I think.
@@BuyitFixit all done I've sent them to u
Thanks mate 👍
Those rivets though >.
Nothing my drill couldn't resolve 😂😂
Sorry Mick.
I have a satire ish sense of humour.
I apologize to both yourself and Vince if my humour seemed slightly abstract .
Unreservedly sorry for any confusion sustained .
No worries, although I've no idea what you're talking about 😂😂😂😂
@@BuyitFixit You're not the only one ......... 🙂
LM358 is a jelly bean part, there is no excuse for not recognising it from the first milisecond you saw it!
And because the damn current transformer is right next to it, an 358 does measure from ground, ofcourse it's part of the current loop ( you need no degree to know that, it's basic electronics ).
On the other hand measuring the mains bridge is pointless since the fuse is ok, also the power transistors must be ok just because the fuse is fine...
I've seen this channel recommended on eevblog forum by someone, but i see it's a waste of time, there is no substitute for electronics theory, and that you do not have unfortunately...
Sorry if it's not up to your level of expertise. I don't profess to be an electronics expert, and that's not the purpose of the channel. I'm just a guy that fixes stuff and a fair few different things (the idea is to help people with similar broken items repair theirs). Remember someone else may have one with a faulty bridge and now they know how to test it. I've fixed a wide variety of stuff from Thermal cameras, a medical ultrasound scanner (which I also unlocked ton of hidden features and ran DOOM on) to solar inverters where I even had to reverse engineer their software and write my own service tool which I made available free to download to help others. No, I don't know everything, and I do make mistakes.
@@BuyitFixit ok, maybe i was a bit harsh, so sorry for that.
It's just that in all i do regarding electronics engineering i strongly promote electronics theory because i believe it is the only way to evolve in a better version of yourself.
And LM358 it is by far the most popular opamp out there ( that is why it's called a "jellybean part" ), it's one of those opamps used just about everywhere by everyone, and every electronics person knows it...
On the other hand, sorry if i have to be somewhat rough again, but if someone does not know hot to measure a bridge rectifier then someone should stay far, FAR away from line powered switching supplies, they really kill those that do not know what their doing.
I guess i can relate to what you are trying to do, so good luck, maybe ill stick around.
Happy holidays!
@DjMarik78 Thanks 👍
do not take apart a p s u if you don know what are you doing let a pro fix a p s u