Sony Bravia KDL-V40XBR1 works great when cold but, no picture when warm

[savageone]

Ok guys I need help trying to narrow down the problem with my Sony LCD TV. The TV operates great with no issues, IF turned on cold, after sitting idle for awhile. If the TV has been on for awhile and turned off, when the power is turned back on, the picture will not come back on.

When the power button is pushed to try and restart a TV that has been ON for awhile, and then turned OFF and then back ON, this is what happens after the power button is pushed:

1) The green/stand by light comes on and you can hear the relays clicking.
No red lights.
2) After 10-15 seconds the back light will come on.
3) After 30 seconds the sound will come on by itself. Channels can be changed at this time.
4) After 45-60 seconds sometimes the picture will come on, but with vertical stripes of all colors.

I have done alot of searching and it seems like I have a problem in the Power Supply board, or possibly the T-con board. I think a bad capacitor is highly possible. Can someone walk me through the steps to diagnose the problem?

I have a Fluke meter, soldering iron, etc.

[savageone]

Re: Sony Bravia KDL-V40XBR1 works great when cold but, no picture when warm

Edited info.

Ok guys I need help trying to narrow down the problem with my Sony LCD TV. The TV operates great with no issues, IF turned on cold, after sitting idle for awhile. If the TV has been on for awhile and turned off, when the power is turned back on, the picture will not come back on.

When the power button is pushed to try and restart a TV that has been ON for awhile, and then turned OFF and then back ON, this is what happens after the power button is pushed:

1) The green/stand by light comes on and you can hear the relays clicking.
No red lights.
2) After 10-15 seconds the back light will come on.
3) Sometimes after 30 seconds the sound will come on by itself, but the volume can not be adjusted. Channels can be changed at this time.
4) Sometimes after 45-60 seconds the picture will come on, but with vertical stripes of all colors.

I have done alot of searching and it seems like I have a problem in the Power Supply board, or possibly the T-con board. I think a bad capacitor is highly possible. Can someone walk me through the steps to diagnose the problem?

I have a Fluke meter, soldering iron, etc.

[savageone]

Re: Sony Bravia KDL-V40XBR1 works great when cold but, no picture when warm

Took the T-con board out today to inspect and get part numbers and I found something interesting. The board is oozing a silicone like grease from some of the components on the top side (middle top). On the corresponding back side there is evidence of some high temperature marks on the board. The board had to be positioned just right for the markings to show up on the pictures.

Is this the answer to my temperature related problem? I don't know, but since i'm talking to myself, I'll let you know when I answer my own question.

[newtothis]

Re: Sony Bravia KDL-V40XBR1 works great when cold but, no picture when warm

*** Please don't start new threads for the same set, I have asked a Mod to remove the other one ***

Ok to me that looks like flux that hasn't been cleaned off and the board has been reworked before. The heat marks may be an indication of this too.

Do you know the history of the set?

[Logistics]

Re: Sony Bravia KDL-V40XBR1 works great when cold but, no picture when warm

I know this thread is old, but doesn't that look more like tech-spray? The protective coating that looks like clear-coat? I only learned about it because I used to work at a manufacturer of electrical transformers, and I found a can of the stuff, and tried it on a few panels to see what it looked like. Looked like this, essentially.

[Logistics]

Re: Sony Bravia KDL-V40XBR1 works great when cold but, no picture when warm

Okay, I happen to have acquired one of these sets, and my Paps was using it at his place as a display for his laptop because his screen is jacked.

Apparently, after about a week of using it in the morning and during the evening, the screen would go blank or it would turn itself off--he can't quite remember. But he was always using the VGA input.

One side-note is that the larger fan was making noise, and obviously not running smoothly.

I took the back cover off, and I don't see any obviously, malfunctioning caps--no bloating on top nor at the rubber bung, no electrolyte leakage. However, I did not remove all the metal casing from over top of the VGA portion, which is on its own board.

I automatically want to recap everything to get as much life as possible out of this set. Obviously, as it creates a ton of heat I feel new fans are in order.

Another thing I noted is that it uses a 119mm fan as the primary. This is very annoying because 120mm are so much more plentiful, and with so many more varieties of blade configurations. I'll have to see if I can get a 120 in the factory location.

Anyway, all input you guys can give me on what should be done is much appreciated!

Matthew