Monitor Problem: Horizontal Lines/Tearing: LCD problem or Power Supply?

[abc619]

Hello everyone,

So I have a monitor that I stupidly bought for $65. And the problem it has is that after about 10 minutes use, the screen will start to show these horizontal lines that go across the screen and would look like some REALLY bad tearing and some static or noise in those tears.

I just wanted to get a second opinion to see if any of you fine knowledgeable fellows might know if the problem is with the LCD screen itself, or the power supply inverter. I know its a problem with one of these components because I took it apart and if I whack the back of the monitor, it will fix the issue, albeit temporarily.

Below I have a picture of my monitor's specific power inverter (for those of you who are curious). I could go out and purchse a new one ($45), but I'm not sure if it would fix the issue.

Picture of my monitor's power supply inverter for those of you who don't know what one looks like

Below is a picture that I photoshopped to simulate what the tearing sort of looks like:

Simulated picture of the problem with my monitor

So I could have power supply inverter replaced (costs $45). But if the the LCD screen I'd rather not get a power supply inverter forget about this monitor all together..

__________________________________________________ _________

For those who thought it was too long to read:
Problem: LCD lines tearing (see spoiler 1). And I already spent $65 on this thing.
Question 1: Is the problem with the LCD panel, or the power supply inverter (see spoiler 2)
Question 2: Is it worth getting a new power supply inverter ($45) if it fixes the problem? Or should I trash this monitor?

[McSteel]

That picture is not of your monitor's I/PB, is it? That one looks to be recapped, and with Panasonic FRs, no less. Looks decent, no heat damage. Are you ready and willing do disassemble the monitor and provide pictures of the I/PB and MCU PCB?

The fact that a whack solves the problem, even for a couple of minutes, probably means you just have a cold solder joint somewhere. If you have a soldering iron handy, and are willing to post detailed (as sharp as possible) pics of both PCB undersides, perhaps we can spot the potential candidates for a touch-up?

[3870x2]

This issue is most likely due to caps having gone bad. Lucky for you, it is an easy inexpensive fix.

You need to check to see if the caps are exploded, even a little bit, on the sides, or more predominantly the top.

[AsRock]

Originally Posted by McSteel

That picture is not of your monitor's I/PB, is it? That one looks to be recapped, and with Panasonic FRs, no less. Looks decent, no heat damage. Are you ready and willing do disassemble the monitor and provide pictures of the I/PB and MCU PCB?

The fact that a whack solves the problem, even for a couple of minutes, probably means you just have a cold solder joint somewhere. If you have a soldering iron handy, and are willing to post detailed (as sharp as possible) pics of both PCB undersides, perhaps we can spot the potential candidates for a touch-up?

Yeah could not agree more that it sounds like dry joints due to what you stated that he has to knock it to make it work correctly..

Good thing easy to fix just might take some time finding it. If you cannot see one might be worth getting the high res camera on it and checking the pics after.

Good Luck..

[Frick]

A magnifying glass is your friend.

EDIT: If you happen to have sometthing like this, even better.

[abc619]

The power board inverter shown is the same model as mine, i just found it off some website. Same caps and stuff based on the colors of them.

But I did manage to take out the power supply board and I did not find any bad/blown capacitors. And looking at the underside, I couldn't find any cracked solder joints.

I could replace some of the capacitors thought since I'm at school and my school has a shop where I could get some replacement capacitors and solder/desolder some stuff.


But now I think I made things a bit worse. After I took the board out, I put it back in the monitor and tried to turn the monitor on, hoping that maybe taking it out/putting it back in would fix it.

Now the monitor LED indicator light turns on for about 5 seconds and the screen stays black. After about 5 seconds, the screen quickly flashes and then the indicator light turns off. And it repeats. I think I might have knocked a capacitor out of place, or one of the larger components (like the transformer or inductors)? Does this turning on/turning off sound like something I can easily do with a soldering iron and replacement capacitors?

[McSteel]

The caps are most likely just fine, I wouldn't worry about them too much.

As for the on/off problem, it seems like you made a short somewhere, and it's tripping the protection IC on the Inverter/Power Board. Probably the output that goes to the backlight inverters. The power supply on there has two rails, and most likely they are 5V (to the MCU) and 12-15V (to the inverters). If you have a digital multimeter available, you could check the output value of both, to see where the problem lies. Also, try turning your monitor on without fully assembling it, but make sure everything is insulated properly, and that you absolutely do not touch the live AC part of the PSU! If the monitor works this way, probably some leads are touching metal parts and shorting out.

[abc619]

So I had the chance to replace the caps to fix the horizontal line problem.

I've included pictures of the inverter board for those of you who are curious. Also please excuse my poor soldering job, I did this before class so I was in a hurry. I plan on resoldering some of the when I get the chance.

But as for the power issue, how would I use a multimeter to check if there is a short somewhere. What exactly should I be looking for?

animation of my issue + pictures of my the power inverter board

GIF of the current issue powering on/off, click on link to view