LCD Monitor Repair - Replacing & Testing Capacitors with ESR Meter
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- Опубликовано: 21 сен 2024
- Learn how to repair an LCD monitor in this easy to follow, how to video guide. Faulty capacitors are usually the problem preventing an LCD computer monitor from running intermittently if not at all. We demonstrate how you can quickly determine if a given cap is bad using an ESR meter that can even check caps in circuit. Our ESR meter is a Atlas ESR70 from Peak Electronic Design Ltd.
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Inspired by videos just like this, and soldering/desoldering tutorial videos, I repaired an LCD monitor about 6 months ago, with reclaimed capacitors from - yep - a PC motherboard. Still going strong, so I'm very happy. My first electronic repair! I've now a nice little collection of capacitors of various voltage and capacitance. I also have a hard drive/DVD video recorder that needs recapping, but I bought 2 new caps for that. Dead PC boards are also good for just practising on.
MarkTheMorose Watch out or your collection will grow like mine and you will need a shop to put it all in :)
I personally go with United Chemicon, Nichicon, and Panasonic caps with great results. You can get a used Sencore LC102 for just a pinch more than that Peak and it will test caps at rated voltage plus do additional tests. I scored one for cheap on Ebay but had to make leads with low capacity coax and find a suitable switcher power supply for it, but still. Maybe the Peak couldn't find a definitive fault with the obviously faulty caps because it can't test them at rated voltage? As another poster said, they all tested within 20% and theoretically should have worked. When the ESR is 0.00, then test the cap with your regular DMM and see if it is directly shorted. A vacuum pump desoldering station ZD-985 is $140, or a ZD-915 is just over a $100 bill. EEVblog did a teardown of the 985 and found the quality quite good. Works a charm. Toss that plunger or give it to a teenager for zit removal. Never understood how you could ever use one of those things effectively especially on multulayer.
I have been working on monitors and TV's for over 30 yeas and I think you explained it well. I like what you do. thanks a bunch it is true bad caps on screens usually the problem especially the fast blinking lcd TV's too..
I used to repair TVs for 20 years back in the 80’s and 90’s.
I had the professional box style analog esr meter. Cost about $135 back then.
That esr meter helped fix many power supplies, vertical, horizontal circuits! 👍🏻
I learned the meter well and questionable measurements but learned to trust it 99% and trust that changing a few more capacitors in doubt was only a few cents more.
I’d usually end up replacing an average of 4 to 6 electrolytic capacitors for the power supplies.
Common problem!
Usually symptoms were intermittent power on/off to unplugging the ac cord and plugging back in to get power to won’t turn on at all.
Usually a gradual failure.
About the percentage value etc... I’d ignore the math and just change the cap regardless. It was cheaper to do it than to rely on the math.
If the caps are anywhere near the circuit path... just change it.
Caps were about $5 bucks for 500 assorted values.
Thanks for the video especially taking the thing to bits I have seen other vids where they were prying with screwdrivers making quite a mess.
I turned my monitor on today and it has horizontal lines on the screen and all the icons for windows etc have a ghost image/relection an inch or so above the the proper image also the image is juddering. could this be down to a blown capacitor?
Great tutorial, thanks... John :)
Good to see you back. My dell monitor was doing the same thing but mine kept making a sound like a robotic arm was trying to move and my power light kept flashing.
A. Young Hello, thank you, I have heard faulty inverter transformers make strange noises from the coils resonating in the past. Possibly your is having that problem.
Sound like a problem with the auxiliary cap that provides and filters the startup power to the switching regulator. Look for a tiny cap in the primary circuit: 10 to 47µF, low voltage. Might also be the over-current protection that periodically switch off the PS: look for a short on the secondary parts (could also be a defective cap on the user side...). I've seen once a problem with a defective resistor, very low value, used to monitor the current in the switching MOS FET... Just guessing, if it could help.
What's the best way to drain the capacitors?
Thanks for the video but in this video I saw ESR meter is useless. If you change all caps why to measure it. Also, Peak device measueres caps exactly what 7 dollars lcr meter does... Giving hundreds of dollars seems to useless. Am I wrong?
This ESR instrument is professional. The point is that at least at the time of shooting this video, he had no idea of what the ESR is. The proof is that he replaced a capacitor showing zero ESR, which means a perfect in health cap, while all the rest he replaced were in excellent condition. For sure the problem was hidden elsewhere. ESR meters are indispensable and this video makes the wrong impression about them...
Apart from that, he should know that there is no way to measure capacitance in circuit. That's why ESR meters were invented. To bridge the gap...
ESR meter is a great idea but a bit on the expensive side. Reclaiming good caps is neat but new is better. I use Mouser or DigiKey for my cap supplier. Good video!
Very nicely explained, thanks for sharing
Good Job
You made a very nice tutorial video. Thanks for inspiration. my acer h163hq lcd monitor's 2A slow blow fuse blown. I'm planning to give a try by replacing those caps that you replaced. what could be the other suspicious components blowing up the fuse??
It would be something on the power supply side. Chances are very good it's a cap but could be a faulty inverter for the back light as well.
All those caps you replaced were within 10% of the rated value, and had good ESR. Order electrolytics, and you'll find that the average is rated at +/- 20%. You may have possibly repaired an intermit when you soldered those caps back in. But whatever, glad the monitor was fixed.
I agree with your thoughts.
Computer motherboards can be troubleshot and repaired using this same technique. Focus mostly on the filter cap supplying the cpu. Look also for electroylitic ooz coming out of the caps as well. Fixing them is time consuming but rewarding as hell.
I own and use a Pace PPS 85 soldering/ desoldering station and It's a masterpiece of engineering! If you do this a lot and have the money, you will never regret buying one but the handpieces seem to never be included for some reason. It's a real gem. Look on Ebay.
+Thema inproblem Ya, Thanks I looked it up and $250 used on Ebay. Hummmm anyone want a review for this :)
I really think that you would like it a lot. Consumables can be purchased on Amazon from Techni-tool. Pace really makes some great products. Lastly, I really enjoy your presentation. It's very nice and laid back and easy to watch and listen to. I want a review! In my opinion it was a good decision but I want yours!!! :-)
I want to modify my previous remark. I think Pace's early gear lacked style and I would not commit to it based on it's look alone. But the station that I have now is a masterpiece in my humble opinion.
Steve, contact me privately if if you decide to pick one up.
When you are shopping around for your caps from digi-key or where ever, first take a harbor freight digital caliper and measure its dimensions. Physical size, distance between leads. (This is important.) Pay attention to gurubrew advice on capacity and voltage specs. Shop carefully and try to buy higher end products. I personally won't install used components ever, because I don't like going back in for a secondary failure. But that's just me. There are lots of really nice motherboards out there that only need new filter caps installed. I'm sending on a restored one right now.
+Thema inproblem You look a lot like Steve Martin, the resemblance is uncanny ;) Good Tips!
+GuruBrew
I get that a lot. :-). Sometimes people mistake me for a jerk. :-)
Let's be candid, high quality low ESR capacitors, particularly for computer monitor power supplies are cheap. I replaced all the caps, with the exception of the mains cap, in three Viewsonic monitors with Panasonic & Rubycon caps for less than $12 US.
I love that ESR meter but its way out of my budget with shipping costs to downunder.
Very clearly explained. And if we talk about ESR meters you can get absolutely working device from china sent to you, all together 10 - 40 units of ur money
You should get you a desoldering gun, There are several good ones, I like and use the xenon hot air gun, it will do surface mount pretty well as well.
Leonard Legg Yes, thanks you are right, I need to get a proper desoldering gun. I had one and it fell off the table a broke. It was just a cheap one so I pitched it in a fit of rage. I noted that the better quality ones run over $200 US so that is a little hard to swallow. Steve
GuruBrew Yeah I understand. I think I paid about $140 for the xenon, but that was 15 years ago and I am still using it, and I used it several times a day there for several years as the lead bench tech at a casino. I could get as much good out of it as other benchs were with $12,000.00 desoldering stations. Probably the most useful electronics tool I purchased since the multi meter.
Great tutorial, thanks I like the ESR meter I need to buy one
There are Gold plated needle-sharp probes available for the ESR meter, so you do not have
to use the 2mm connectors as a probe.
Question: I'm running duel monitor system and my second screen just went black...on reboot it loads and goes in and then I see the display for about two seconds and it goes black again...if I hit the buttons on the monitor sometimes I get a flash of the display desktop and it goes back black. I have replaced all the caps on the Powersupply board besides the actual Large one. Any Suggestions? It changed nothing with new caps. I don't have an ESR meter.
All the caps you replaced were within +-20% tolerance this makes me doubt it was the caps.
I just thought the same, it is possible that the problem was elsewhere
Monitor still working well today (3 years later)
@@GuruBrew Ofcourse & can work more 10+y. lol
Yes, you are right!
Yes, same thought here. I would have considered all these caps good ...
My monitor doesn't even display for a second and the light on the bdoesn't turn on. Could the issue still be the capacitors?
WOW! Excelent.
I learned that we can use high capacity high voltage cap in place of low capacity low voltage but what should be the maximum % values.can I use 1000uf /250v in place of 10uf /35v?
In most cases you don't want to change the capacitance value at all. You can go up in voltage but the capacitance should stay the same.
As explained by Nun Ya, you can go higher in voltage. Depending the use of the capacitor, usually you can also go higher in capacitance (let say +50% to +100%), but keep in mind that this oversized cap will store more energy and not all circuit are able to handle that excess (charging or discharging). If the cap belongs to a more critical circuit (audio, timing, switching power supply, etc.), forget to change the value: the circuit was design for this exact value. As it was well explain in the video, the high voltage caps usually have a higher ESR, not all circuit can afford that change... And one last practical thing, a 10µF/35V is a tiny cylinder while a 1000µF/250V is a huge cap!
The issues with bad electrolytic caps is not limited to just monitors, but is the primary cause of failure for most power supplies in electronic hardware. An ESR meter is an excellent way to test these caps and will pay for itself usually in the first repair.
hankus253 Hello, I have a bunch of monitors and TV's that I have saved that are not working that require my attention. I am set with a lifetime of electronic viewing devices :) Does your auto leveling work on the 3D printer now?
GuruBrew As a matter of fact yes, ABL is good and my cabinet just needs paint and the acrylic windows installed and that phase will be complete.
I agree. I have replaced many caps in both monitors and power supplies and saved quite a bit of valuable equipment from the recycle bin.
Good video. I have a Samsung with a white screen. No image. Backlights seem to be fine. What do you think is the problem?
TCON board
@@NunYa953 TCON board. Could you suggest a source? I have a question if you know. I see 2 caps that look suspicious. A little puffed on the top. Very little. A lot of videos are saying that changing out bad caps can solve the white screen and that a TCON swap is sometimes unnecessary. Is there any truth to that.
@@alext9067
Here is what I would do: if the caps look even somewhat suspicious then change them. Ideally you should test them with an ESR meter. If you don't have access to one then the caps are dirt cheap. Always suspect caps first because they the most common failure. They are also the easiest and cheapest to replace. If caps don't fix the problem then it may be the TCON. A TCON is definitely not as common as caps. Make sure you know the rules for changing cap voltage capacitance etc
@@NunYa953 Ah, thank you. Good logic. I just need to make sure I get the right board. There are paper labels and I'm assuming that the board would have a number printed right on it. Is that a safe bet? Or do I use the model number of the monitor? Do you think eBay is the place to get it, or someplace else? Thanks again.
@@alext9067
If it's just capacitors you don't need to buy a board. Buy the caps and change them. When buying boards you ALWAYS go by the stickers as there are usually multiple "versions" of the same model.
If you measure any brand new capacitor you can buy today, you will NEVER measure the nominal capacitance written on its body. This is due to the cost reducing target all cap makers like to hit and they do. Especially as regards cheap caps, I have many times measured, for example in the main filtering stage of psus, 220μF instead of the 330μF written on their body, while their ESR was perfect. In this case the theft is obvious. So the only interesting criterion, for cap health and/or quality, remains the ESR value as the absolute criterion.
In this video, two things were wrong. First, when checking in circuit these caps, one needs to wiggle the cap while watching the ESR value. This will reveal intermittency of the capacitor ' s internal bondings with its external terminals. This was not done and is a mistake. A faulty cap can easily escape when measuring ESR in an absolutely static way. The second mistake, usual with instruments that monitor both capacitance and ESR, is to take into account the capacitance value. For in circuit measurement of caps, the capacitance parameter will simply drive you crazy as THERE IS NO WAY TO MEASURE IT IN CIRCUIT!...
GuruBrew
As you insist on inserting mucic into segments of your presentation,
consider equalizing the volume with your voice or just below that.
The music is overpowering thus requiring the Volume to be turned.
so as not to damage our hearing, then the Volume increased when
you speak..
The Music needs to be subtle as it is secondary to the presentation.
It is not a music video.
Thumbs down on that basis.
Please take the recommendations to improve your presentations,
Study how music is I'm[plemented in the videos of professional
documentary makers.
Good luck and 'Brew a better video' It's not that difficult.
PEAK instruments are manufactured in DERBY UK.
A place I know very well
It is the hometown of my (late Fathers niece) who migrated (decades ago)
to the UK from the state of MI USA.
Her son works for ROLLS ROYCE JET
are there any testers as good as this one ???
Yes, the "blue ESR" meter designed by Bob Parker. Excellent instrument.
My ESR meter is analog and while it's a great tool it's not fool proof. It can really point you in the right direction, trust but verify. Shop at digi-key, Allied or Newark. If there is any doubt at all, toss a new one in. They are cheap.
+Thema inproblem Well Said
+Thema inproblem I used to work in a tv repair shop and all of us used those ESR meters. I think it's really a useful tool and it was really a quick easy way to test them. When you work in a shop time is money.
i have a emachine made in 2000 but its windows is corrupt and i don't have the right keyboard and mouse for it it has usb ports but the mouse and keyboard don't work it uses ps/2 can you install windows xp on it and get a mouse and keyboard that works on it and if so how mutch would it cost
elementalfox gaming Yes, you will have to get at least a PS/2 keyboard to install the XP software as a USB port wont be recognized until Windows is completely installed and running but once it is you can use your USB keyboard and mouse. A PS/2 keyboard can be found for very little if not free. Ask a local repair shop if they have any or check a thrift store. As far as the XP software install disk, if you don't have it then check on Ebay, I am sure you can locate it for really cheap. Have you tried restoring the corrupt software? look in my videos for how to restore a machine if you don't know how, as this might save you from all the above actions. Best of luck.
thx money kinda tight considering i'm 13 so thanks
It complicates your life a lot to get the energy, it is better to add the new one and remove the condenser. Much easier, faster and safer!
they caps you replaced are all good caps within tolerance errr makes no sense
These caps have such a bad track record I'd save the money buying the ESR meter and buy quality high temp Panasonic caps from Mouser or Digikey. Fix once, use new caps... time is worth the xtra $$$. But then ya know what they say about opinions!!! Still like ur vids... new subscriber.
wb8cxo Welcome and thanks for the sub. I admit am cheap when spending money on my own projects as I feel guilt if I don't recycle what I already have :)
Gosh you spend a lot on solder wick.
yeah you sound week, never heard you like that.
So far not impressed with your tester, need to check into a sencore LC tester. Matter of fact I have an extra one I been thinking about selling. An LC 56 I believe it is.
Just 10% less capacitance and the monitor stoppes working ...
I never trust in circuit capacitor test, particularly with ESR tester.
Maybe you should learn some electrical theory.
Honestly man, your video scared the shit out of me. Throwing out random statements like "it's ok to go up in capacitance" is just ridiculously irresponsible. If they're filtering caps on a power board then sure, but any other time you just disrupted the functioning of the device. Changing the capacitance of capacitors can alter the wave form of signals on the board, disrupt timing within devices. Your statement as it was made is simply wrong.
+Stephen Garner YES, you are correct and I should have added in a statement specifying this practice only pertains to filter type cap...,Like the ones on a power board, we were working on.
Conclusively, the capacitors are the problem & need to all be replaced due to their high resistance when they dry up inside or blow or bulge even. ipso facto. Troubleshooters conclusively won their case. Ipso facto