Signal Collapeses after a Few Seconds Toshiba MV13L2
 

Hello all! Thanks for accepting me into the forum. I am working on a Toshiba MV13L2 with the following issue. It turns on, I get good static screen on channel 3 with static noise for about 3-4 seconds, then it distorts, and then goes dim. The static screen is still there, dark but there, the sound goes away completely. This is true for Tuner IN, VIN, and VCR in. They all do the same thing, loss of picture after a few seconds. Another clue, the MENU overlay/ CHANNEL/ VOLUME etc. Looks great. It gets "wavy" after some time, but is not dim and bad like the rest of the picture. See my attached videos. I am mostly out of ideas

I have done the following:

Verified good 5v and 8v. I did this at a single place on the board, not right next to the Jungle IC. I need to go back and verify 5V right next to the jungle IC...

Replaced pretty much every capacitor that has to do with the power to the Jungle IC and around it.

Video shows the two different screens on boot, TUNER and VIN.
Link to video of issue: https://www.youtube.com/shorts/CqER-i8tcRQ

I would think that make you have something wrong with the main video IC and not the jungle IC. Because the OSD works, that could indicate that things are okay downstream from where the IF and whatnot is taking place

It could be something around that IC or possibly a cracked solder joint or something. Maybe if there's a video input board it could also be around there.

One thing you can try is to use cold spray (or a can of compressed air upside-down) and freeze the IC or things like supporting transistors around that area. What you would be looking for is some kind of clear and obvious change in the picture when you hit a specific component with the cold. Sometimes (not always) that can momentarily repair a failing component to give you a clue. I suggest this because you seem to have a problem when it warms up, so it's possible that it's temperature related

Other than that not sure. I don't have as much experience as the older members of the forum, but hope that helps a bit.