LED Computer Monitor Repair

[@LearnElectronicsRepair]

Well I didn't have to soak test it for long. My wife (Julie, by the way) used it for a few hours this morning, but as she was sending an email when it suddenly went blank, then came back on with narrow multicoloured vertical lines all over the screen (looking like a duff GPU). I unplugged the monitor power and powered it back up again but now it doesn't come on. Julie's PC had not crashed, I connected a spare monitor and it was working.

[@gorky_vk]

Sounds like bad solder joints somewhere on media board, I'd bet it will start working same moment you open it next time.

[@Nelox2000]

Hi Sir, it has nothing to do with the video, but I see that you know a lot. I found on the thrash a gtx titan x which was not working, when I opened it up, i saw that it has a high side mosfet burned and an inductor (r33) burned… the electrical engineer team of my company told me that they will help me, if I find the compounds. Do you think it will work replacing this pieces? Or the 12v reached the gpu, or vrams and it is non sense? The rest of the gpu looks glorious besides that two compounds. Cheers, and sorry for this question, I know it is not related with the video but I can not find the answer nowhere

[@LearnElectronicsRepair]

@@Nelox2000 Impossible to answer that, but usually short circuit high side mosfet does tend to kill the GPU, Vram or both. I would take some resistance measurements. GPU Vcore will read very low anywau, but if you see a near short of Vmemcontroller, PEX or Vram it doesn't look good. Expect PEX to read 10-20 ohms or so, and Vmemcontroller to read maybe 30 ohms or so.

[@Nelox2000]

@@LearnElectronicsRepair thank you sir, i will let you know what happened once i change the compounds. I will take the measurments also. Greetings from Argentina.

[@bittertruth6575]

Could be a bad cap somewhere misbehaving when it gets too hot. I had a similar issue with a samsung one where it kept going off under load and then would turn on after a while. Fixed it but then the backlight went on it. Might be a good idea to check them one by one.

[@goranaxelsson1409]

Reminds me of a LED TV I got in a couple of years back. The error was that it stopped working after 15-30 minutes. So the guy loaded it up in the car and brought it over. I opened it up and checked for any visual cues.. nothing. Then I just put a movie onto it and did other stuff while it was playing in the background. Worked perfectly. So the guy got it back and it worked fine for him too. A year later I got a new call. The TV had worked perfectly for almost a year until the error appeared again. This time it didn't start at all so time for round two... I opened it up again and now I could see the problem, a burned connector for the power going in on the main board. The connector showed a brown spot on the plastic. I quickly stripped the wires and soldered them straight onto the main board and the TV worked again. Apparently the connector had a thermal issue and failed open when it got hot. When I opened it the first time it was enough to break the oxide layers and create a better connection, allowing it to work until it eventually failed. So nowadays I check the power connectors if I don't find any other fault. The first sign of an overheated connector is the tin plating turns gray and dull compared to the pins around it. In extreme cases the plastic of the connector turns brown or even starts to char.

[@rafak9177]

Hi Rich, I fixed a few monitors recently. I find old plastic cards (like credit cards or loyalty cards) very useful when prying open the back cover. Stiff enough to do the job, but also flexible and won't snap. Just be careful as the top layer of the foil peels off and particles can stay inside the monitor. Cheers!

[@LarixusSnydes]

I really like that the manufacturer has clear, descriptive silk screen printing on the PCB and printed different dash and cross marks on the outgoing flat cable. This makes it much easier to track continuity between boards in case there is a twist in the cable on the way to the connecting board.

[@powerplay8355]

My dead monitor was a broken track on the neutral input to the board. Took it out - working, put it back in - not working. This kept happening until the break on the track became visibly noticeable. Blob of solder and some wick fixed it.

[@mikasa1641]

I had a similar issue and it turned out the physical push button was defective. Everything was fine after replacing it. It was the first I've seen these little buttons breaking causing a loose/intermittent contact

[@TheDurdane]

I also think power button. There is too much current spike turning on and off. It would better if there was a relay between the main and the PSU, but then again that is probably too expensive, since these monitors are so cheap in relation to ten years ago...

[@RickL_was_here]

That was my thoughts as well.

[@LearnElectronicsRepair]

@Mr Guru Exactly

[@LearnElectronicsRepair]

The monitor should power up automatically when you apply power, then go to sleep until the PC provides a signal

[@craigcousins6718]

Another thought could it be a dodgy IEC cable? Or dry joint on power input socket from being plugged in and out etc..

[@CliveChamberlain946]

Those metal pieces on the pcb top are cheapo heat sinks soldered really close to the tabs of the smt mosfets on the bottom.

[@juseth2]

I had this kind of problems with my computer many times, and other things. This is so typical! Great video! I think I learned a few new things.

[@CTCTraining1]

Intermittent faults are the most annoying. I’ve had some success with freeze spray revealing dry solder joints in the past. Yes, soak tests for things which fail during use are worthwhile but if something doesn’t start without tinkering (TLC?) I’m not sure burn in testing would necessarily reveal the condition. Maybe a warm air / freeze spray ? Hopefully it will return for a part 2 😀👍

[@andygardiner6526]

Tap around with a screwdriver handle and wiggling wires followed by freezer. As someone else has mentioned, I would wonder if the power switch is used regularly and is intermittent - some are never used as the pc is turned off instead but it's worth a look ...

[@LearnElectronicsRepair]

As this monitor is used by my wife at the workshop it is easiest to let her use it and see what happens.

[@andygardiner6526]

@@LearnElectronicsRepair let her soak test it :-) To be honest we used to use loads but given the current price of freezer it's not worth using much! Hell, "they" even wanted £15 for a can of my normal flavour of air duster!

[@uksuperrascal]

@@andygardiner6526 Add a car or push bike tyre valve to your old empty air duster can and refill with bike hand pump OR 12V car air pump.

[@faridsafazadeh1137]

you are such a nice and honest guy. I like you and your clips.

[@andymouse]

Your right ! most people would correctly go straight to the power supply with these TVs...cheers.

[@chinnarao326]

Resp Sir! Excellent Class Sir. -- ChinnaRao Paderu Visakhapatnam Dist Andhrapradesh

[@SEOng-gs7lj]

have you ever repaired LCD display of DECT phones? the panasonic ones are always prone to blanking out

[@marcellipovsky8222]

Hi Richard, you mentioned it many times now (and we've seen it) that the humidity and salinity of the Island's environment causes a lot of corrosion. It really could be as simple as that the power button and other contacts got a bit corroded hence increasing the resistances and causing the intermittent failures.

[@jonnafry]

Yes indeed, I"ve had that power button scenario a couple of times with various monitors.

[@LearnElectronicsRepair]

This monitor should power up without pressing the power button so I doubt it is that.

[@seeithappen1]

That is simply not true. For example cars on gran canaria last 2 times longer because of the sunny environment and the lack of rain.

[@marcellipovsky8222]

@@seeithappen1 AS I don't live there, I cannot judge it. It is just an observation from previous videos. I haven't seen rusted computers here. Dusty? Yes, but no rust/corrosion like on the ones Richard serviced.

[@Del_UK]

I have a few monitors, where the fault is on the driver board. What would happened, is it would not turn on straight away and this was due to a faulty cap. After replacing, it would work and the after an hour would suddenly go blank screen. It turned out that there is a component 3 legs/pins with a heatsink ( I don't know the name of the part). What was happening is due to lack of air flow in case, this part was heating up and the shutting down when it became too hot. I applied some fresh thermal paste and it worked semi ok for about a month and then died completely.

[@user-gj4ei6dc5q]

The saying 'if it ain't broke, don't fix it', is better stated as 'if it ain't broke, don't break it', in my opinion. If I only heeded my own advice on more than one occasion, it would have saved me a lot of time and effort lol.

[@SpaceParanoidX]

Maybe take a look at the control panel. There may be a problem with the switches.

[@LearnElectronicsRepair]

A lot have said that but the monitor should power up automatically when you provide power. Then go to sleep if there is no signal

[@AbdiGezachew]

waw Nice biro but ask you one question same time format may computer (laptop, Dell and other pc) then completed recover may file after format may computer then automatically open recover file by word excel ppt pdf

[@boriscache6350]

Hi Sir. thks a lot for you vids ! Could you make one about how to use an oscilloscope ?

[@therealspixycat]

There is a very small change that there is a short on the led because the leds are in series and therefore the high voltage

[@Denise_in_progress]

Maybe when the processor got warm it shuts down, when it Cools off it does working again. Or you just had to reseat the screen connector, sometimes it's just that and will solve it like laptop's issues with no screen but backlight on as long as the 3 or 5 volt is presenceb 👍.

[@abelzoltan3037]

power switch??

[@LearnElectronicsRepair]

Nope.

[@nitehawk4067]

i have an acer 19 inch 4.3 monitor working 8 hrs a day at works more than 20 years. Only repair i did is changing failing capacitors on backlight power board. it has cold cathode lamps.

[@michellefoster1020]

What software do you use for your video

[@LearnElectronicsRepair]

For recording I use OBS Studio which does the picture-in-picture inserts in real time. For editing I use Davinci Resolve. Both are free software and I can thoroughly recommend them. I record on an i7-4790 with 4Gb of DDR3, and GTX 750 ti running Windows 7 32 bit. I edit on an i7-5820K X99 system with 16Gb DDR4 RAM and also currently using an GTX 750 ti running windows 10 64 bit as my GTX 980 ti was acting up I have just built an i7-7700K with 16Gb DDR4 and RTX 2070 ti to replace my i7-4790 recording PC and I'm about to upgrade the i7-5820K with a RTX 4070 ti. This will allow me to A: do live streaming on KZbin or go up to 1080p 60fps or 2K/4K recording and B: edit videos much faster or at higher resolutions I hope that helps you.

[@Lightrunner.]

No fail 😱 How dare you , you evil monitor. 🤣🤣🤣🤣

[@Meancat3]

Similar troubles with intermittent power button

[@LearnElectronicsRepair]

The monitor should power up automatically without pressing any buttons. You can use the button to manually power it off (put it in standby) and on

[@ISquishWorms]

@@LearnElectronicsRepair Just want to say your videos and channel are great. I wish at school I had you as my electronic teacher (I am old now). Anyway you are probably right although could it be the switch is getting stuck in the off position? What would happen if the switch is stuck closed and you apply power would it still power up and show the logo?

[@peternakogee8449]

where can I order broken screen monitor

[@gordonemery6949]

Did you try thumping it on top ? 😅

[@andygardiner6526]

Had a crt with that :-) "My monitor isn't working." I'd walk in, make a big thing of "laying on hands" to feel the fault, thump it in exactly the right place and walk out again ... used to last at least a couple of weeks :-)

[@peterferguson2344]

Intermittent faults are the worst 😡 my old boss was quite often seen armed with a can of freeze spray in one hand and a heat source in the other to hunt them down 👍

[@davestake44]

Job well done , good video thanks

[@reacey]

Maybe it thinks youre pressing buttons when youre not ,caused by slightly conductive dirt in the switch contacts

[@vivesparkle]

Hi, I have this Dell LCD 2709W for some time now, but about 3yrs ago it stopped turning on, took it to a technician and they could not fix it but suggested i change the board, which we could not obtain anywhere in Nigeria. I packed it up, after about 4mths I plugged it, power it on and voila its working, i used it for sometime and it stopped working again. So i packed it again and after a month tried to power it again and it did not work, so i left it for longer like 3mths plus and power it again and its working. It stopped working last year and i packed it again, i tried powering after a while it did not work, so i left it again for longer, i just powered it on today and its working. Is there any explanation to this? What could be done? Thanks

[@TABE-O]

What is that machine behind you ? Looks like it has a joystick controller?

[@khx73]

BNC in/out connectors... security monitor?

[@hernancoronel]

might be… if it is, it should be built like a tank!

[@LearnElectronicsRepair]

Yes, we had some that came with thermal imaging systems which we were selling during the pandemic and one client didn't need the monotor as they had their own so it sat around for a while then got repurposed as a PC monitor as it also has VGA and HDMI. It works really well for this purpose, or did

[@mUbase]

Timestamp 1:47 I'm Guessing its the diodes in the power section...

[@mUbase]

Timestamp 19:39 Wrongo Pongo. lol.

[@lataishajohnson2117]

Wish me luck I got me a 4k monitor for Christmas was so happy to game on it. Then when I was cleaning my setup my monitor hit my other monitor and fuck up the screen. So imma buy a new panel and replace it myself

[@davide26153]

I had an acer monitor that didn't work with intermittent power led light Every time I disassembled it started working again for a while until it didn't In the end it was defective electrolytic capacitor even if they looked fine

[@TABE-O]

Love your repair vids👌👌

[@ianhewitt1858]

The fault diag vids are great. Showing us some smd and ball array soldering techniques is very apealing. BUT WHAT WE ALL WANT TO SEE is you giving the wife the repair bill!!!!

[@ishkhan2501]

either one or two LED open circuit in LCD panel

[@2009numan]

never heard of that make of monitor before

[@MultiVoiceofreason]

Qvis is a security camera brand they operate under a brand called puretech

[@Hydra-q6o]

I would say the power button?

[@conhawks]

richard, how can i contact , regards clyde

[@taskinyucekurt]

Typical nothing wrong with me but i wont work situation, i have seen one in one of sockets a pin was creating high resistance with pin itseld n sockets pin cuz of that device wasnt turning on cuz there was no enough voltage. Probably this one had that problem, when you pull them sockets out and put them back thing started to work again.

[@jdshenanigans9265]

It may be an oxidized pin or a dry solder joint

[@deafdave6468]

Spending time watching this video I really hoped that there would be an accurate diagnostic to the problem followed by a how to solve it but no sad ending and an total waste of my time!! Epic fail!!! I suppose you wanted someone else to solve it?? Should have called Colombo!!!

[@SolderBrothers]

We call it "chicken foot". You shake a chicken foot at it and it works, lol.

[@shagreobe]

I hate those intermittent problems..How in the world am I supposed to fix something thats working

[@psnvprasad9654]

Still you are not making short vedio for learner

[@MrFujack103]

Probably same as laptops. Unplug the screen and plug it back in lol bad connections on connectors

[@marwanmoussa7221]

I had a cpiple of samsung LED monitors with corroded power button.

[@Dutch_off_grid_homesteading]

Heya oh wouw you have magic fingers lol

[@MultiVoiceofreason]

The problem is it's a qvis monitor😂 designed to work, 1 day more than warranty 🤣 their cams are much the same Dicky.

[@LearnElectronicsRepair]

I didn't actually buy the monitor, it came with some thermal imaging systems we were installing during the covid pandemic and this particular client didn't need it. So it got repurposed as a PC monitor at the workshop.

[@LarixusSnydes]

@@LearnElectronicsRepair I figured as such as BNC connectors are quite uncommon on basic consumer PC monitors, at least here in the Netherlands across the moat.

[@bufordmaddogtannen]

What a disappointment. I was expecting to watch another episode of “the butcher of Las Palmas” and instead you used a plastic spudger. 🤣😂 I’m partial to guitar picks, 5 quids for a box of 24, including a metal box.

[@RickL_was_here]

As someone who plays on occasion, I too have used picks, they work great.

[@granthoughton769]

I'm not wasting picks! Out of date bank/credit cards are free!

[@bufordmaddogtannen]

@@granthoughton769 and Chinese picks come in 5 different thicknesses.

[@Mahesh-jq1du]

Hi @everyone #everyone My aoc monitor is flickering same as this video. Also I'm using a different power supply can any one give me a reason for this.. kzbin.info/www/bejne/g4KximCkatd8mtksi=G7ylWyWwGyzzT3uG

[@alanrichardson1672]

You should check the basics such as is there power to the device (fuses, loose connections etc.) and does the internal PSU have an output before diving in. You can waste a lot time and effort with your approach and is not a good way to teach people.👍🤫 (edit typo)

[@LearnElectronicsRepair]

Alan, I do know how to do those things 😉 I did discuss in the video how to move forwards (waggle wires etc) or put it on soak test and I also chatted about why I didn't check the PSU output before removing and testing it. Of course you and everyone else are welcome... no, in fact you are invited... to express your opinions and you are correct to question or challenge what I do. As I explained this is not a customers item, it is in use at the workshop every day, so I stand by my comments that in this instance I believe it is best to just use it and see what it does. IMHO I would say your suggestions on how you would approach this fault are just as relevant and perfectly correct, but I wouldn't say they are more correct than my conclusion is.

[@gorky_vk]

@@LearnElectronicsRepair with LED screens I always go other way around. No1 failing point is LEDs so I always check them first. Not a professional so I just use homemade tester (high voltage low current tester I made with 555, transistor and 3.3mH inductor :)) and if LEDs are ok then I can start checking everything else.

[@alanrichardson1672]

@@LearnElectronicsRepair Hi Richard, what a masterful pontification, I think you really enjoyed that. 😉

[@alanrichardson1672]

@@gorky_vk Indeed, start with the regular known type of issues. 👍

[@LearnElectronicsRepair]

@@gorky_vk I did want to introduce back light testing in this video / tutorial and just my luck, that wasn't the problem this time - unless it is intermittent. I have one of the commercial back light testers, approx 30V 1ma or 300V 30mA switchable, but I'm very interested in yours it sounds like an interesting project

[@seeithappen1]

First ...

[@Daniel-gr3dk]

Let me discharge the capacitor, since 13v is extremely dangerous... 🤦

[@LearnElectronicsRepair]

That's not the reason I did it. If there is 13V in the circuit, it can really screw around with any resistance measurements you may want to take 😉

[@ianhaylock7409]

He did say he was doing so, because the voltage may affect resistance measurements.

[@LearnElectronicsRepair]

@@ianhaylock7409 Exactly 🙂

[@Daniel-gr3dk]

@@LearnElectronicsRepair But then you go and plug it in again, without making any measurements... I know I seem to be a little too harsh, but you do that a lot, and this is the first time I commented on it...

[@100000suns]

"not that there is a dangerous voltage in this now, but its not easy to make measurements"