sony trinitron KV2781R no picture/no sound

Hello all,
I have a friend who has a 25" sony TV that when you push the power button, the power LED would light, but there was no picture or sound for a minute or two. Then it went like this for 5 minutes, then 10 minutes, then 20 minutes. Then finally it wouldn't come on at all. He left it on for a day. Any ideas? Thanks in advance.

Ken B said:

Hello all,
I have a friend who has a 25" sony TV that when you push the power button, the power LED would light, but there was no picture or sound for a minute or two. Then it went like this for 5 minutes, then 10 minutes, then 20 minutes. Then finally it wouldn't come on at all. He left it on for a day. Any ideas? Thanks in advance.

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Being a Sony the first thing to check is for dry joints, particularly on regulators or any components with heatsinks or thick connection wires.

Another common fault is low ESR capacitors, usually in the PSU or field output stage.

But as with any fault finding, you need to try and find out which part of the set is actually at fault - bearing in mind that many sections can affect others.

I absolutely second what Nigel said, check ALL large joints , especially any interconnects and anything that gets warm in use. Some may be hard to spot, but usually they show very fine cracks or dull looking solder.

I've made alot of repairs that involved nothing more than a couple feet of solder and some desolder wick.

RCA ( Thomson ) had massive tuner/micro failures with all sorts of funky problems all due to shoddy soldering.