Sanyo TV repair Help

[Flannelman]

Any help you guys/gals can provide would be appreciated.
So I was given a Sanyo DP58D34 that supposedly had a lightening power surge run through it. What it does is take a long time to turn on and after around 5-10 minutes it quits displaying a picture but the power led stays on. If you unplug it and let it sit awhile it will turn on and display a picture but the cycle repeats.

So I pulled it apart and there aren't any caps that are bulged or blown and the boards all look good other than the power board has a resistor that has some green substance on it that looks vaguely like melted plastic. Since it seems to be a power issue I was wondering if it would be worth buying a new power board($60)? I don't have anything into this tv but it would be nice to have for a size upgrade.

Thanks

 

[Rumpltzer]

It's difficult to diagnose these types of problems on the Interwebz, even if you had given model info and whatnot. Also, AT might not be as wide a forum as you need to help solve your problem. I'm going to tell you what happened in my case, and you can see if it might help you.

My LG 47LV5400 TV went out about a month ago. It was on and all was good, and then there was no picture and no sound and no backlight. Just like that. I popped it open hoping for an obvious power board problem, and I got nothing. I eventually tracked down the service manual and started working through it.

All of the 24 pins from the power board to the main board were giving proper voltages, so it likely wasn't the power board. No voltage was being supplied to the TCon board from the main board, so it was likely a problem at the main board. I was able to jump start the backlights by shorting a pin, so it wasn't that all of my backight LEDs went belly-up at once.

Main board. In my service manual, there's a flow chart that lists debug by testing individual ICs and pin numbers for specific voltages and stuff like that. I went through it until the end, and all was checking out. Final assessment, "replace main board". Blah! The main boards were $120-200 when they were available, but it seems that 2011 was too long ago (????!!) and there are none available. That, and I can pick up a brand new Vizio 48-inch Smart TV for $350 after tax.

Last week, while out of the country on travel, I was still thinking about my TV (it has 4 HDMI ports, four! I challenge you to find a mid-range TV with 4 HDMI ports these days.) and I found a pretty new Youtube video where the guy was fixing an LG TV using a halogen light bulb. He says that people on the Interwebz have been fixing bad solder balls (BGAs) under their LG CPUs by baking the main boards in their kitchen ovens. I Google into this, and he's right! There are forums where people are taking their main boards from 2011 LG TVs, baking them at 385F, and the TVs work again. At the same time, stinking their house up and probably giving themselves cancer... but their TVs are working!!

I work in semiconductors. I help with packaging. I understand solder balls and assembly and all that. I HAD to try it. I used my halogen desk lamp ~2cm from the CPU. My TV works again. I replaced what appears to be a silicon pad between the CPU and heat sink with Arctic Siver. We'll see how long it lasts. If it dies again, I'll go at it with a heat gun instead of my desk lamp.

Good luck.