/diy/ - Do It Yourself

>>2015749

>>2015749
well just fill this out in advance.

>>2015749
C154 and C107 are the most likely culprits. They're the filtering for the power supply. All of the ceramics for coupling and bypassing I can guarantee are not the issue.

Possible the switching FET or the output diode in the power supply is bad too but I'd expect the TV to fail to power on in that case.

You need to get replacement caps of the same capacitance, voltage rating, type, and package size. And I hope your surface mount soldering skills are good. They are relatively big parts but have small pads and the high component density means if you bumble around like an ape you're probably damage the components nearby.

Anyway I'll let you figure out the rest. I've already spoonfed you enough. Good luck.

>>2015945
been looking for this for awhile, do you have the template?

Thank you for your generous reply. I was thinking that capacitors were all the larger electrolytic style. I saw multiple labeling styles for the details so I wanted to confirm I would be getting the right kind. I see now things are more complicated and my question was too open ended.

If the capacitors were really bad, I'd expect the monitor to not work at all. The fact that it works normally for a few seconds tells me something else is wrong.

Does the monitor work better or worse when you get it hot or cold? That can be a good way to tell if the issue is solder joints.

I put it outside in the cold for a bit and it has now stayed on for a few minutes.

Now it's blinking on and off. If it's a solder joint I assume it would be hard to track down which one, right? I looked pretty closely at the back of the board when I had it open and didn't see anything wrong with the joints.

>>2016057
That's only one failure mode. If the electrolyte dries out that will drive the ESR up and increase DC leakage and other things. You may get a large ripple voltage that you shouldn't. If it's large enough the power will dip enough to shut the TV off, alternatively, the MCU detects the dips and auto shuts off if it drops low enough.

Where is the power supply? Is it an external brick?

Actually it seems to be only blinking when the video is connected and is staying solid for now when it's just power connected after putting it in the cold again. If it is those electrolytics is there a special way to get them out? They didn't look like they had a joint on the back of the board to desolder. I appreciate all the help and I apologize if these questions are too basic. I'm finding it a bit tougher to research from my phone.

Yes, it's a wall wart. I don't have anything to switch that out for.

You need to inspect power supply board and not this main logic board

>>2016100
unsolder here, there should also be a joint on the upper part
the connection usually goes halfway under the cap so it takes quite a lot of heat to get off
you can replace with a non smd variant, just match the capacitance. the voltage rating can be higher on the new cap
note the polarity

>>2016014

>>2015995
OP didn't post a pic of the power supply, that's the control board and rarely ever the problem.

>>2016432
>OP didn't post a pic of the power supply,

he said it was a wall wart. a pic wouldnt help unless he tore it apart, which he definitely should do even tho there's a 78% chance he'll damage it.

Yep, I ripped off the ground wire from the plug when opening it, but at least I understand how to fix that. Don't think I screwed anything else up in there. Here's the insides. I'll go pick up the capacitors and try my luck with the main board soon, unless there's something wrong with the power supply.

>>2016096
>>2016432
There's a buck-boost converter on board plain as day. How do you not see it? Two inductors suggest the topology is either cuk or sepic.

>>2016444
the wall wart usually still powers the inverter if it's cold cathode, and often times the power supply for LED boards. issues with the back light are the power supply for the back light NOT the control board.

>>2016644
you have never worked on monitors have you?

>>2016591

that capacitor on the left is bulging some. its bad. did you ever think to try another wall wart to see if THAT WAS the problem? usually the older style capacitors like inside the power supply fail more than the new modern versions (those small silver ones you pointed out before)

I would try a new power supply first before doing any replacement of components.. sometimes its the simple things that cause shit to not work.

Yeah I should have thought of that. I guess I assumed the adapter was an all or nothing thing. The only thing is why would it start to work better when just the monitor itself was put outside in the cold? I will try another adapter before I start screwing with the main board. I don't know if I will be able to sort this out before the thread goes inactive so I can report back, but you guys have given me a great deal of info, thank you.

>>2016832
Listen to>>2016689
The cap on the far left side of the psu is bulging and needs to be replaced, and that might not be the only one that's bad.

>>2015749

>inexperienced techlet is troubleshooting capacitors in a monitor

For the love of god don't touch the leads together, you will get shocked bad.

>>2015749
Its more likely that the problem capacitor is on the power supply PCB.

Practical electronics for inventors. Get it on Amazon or pdf. Extremely handy book.

>>2015749
What did you censor out on the inputs shield?

>>2021775
probably because he broke it.

>>2021775
>he doesn't engrave his name, address and social security number on his inputs shield