Sony 27" Trinitron Dead

Just follow the pc trace and see where the standby voltage is developed. Shouldn't be too long a path. How much experience do you have repairing tv's?

Good luck.

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David Farber
David Farber's Service Center
L.A., CA

first you should look up the chassis number of this set on the internet. Once you it, check if you can find a list with common issues with this set and their remedies. Since it is a Sony set, it should be easy to find. At least, that's my experience with these. I don't have internet access now and I'm writing this post offline with my handheld, otherwise I'd look ot up for you. A very common website for such repair information was

I don't know though whether the site is still up and running. I'd also check good old

Good luck and greetings from Geneva/CERN,

Adrian

Thanks. I've tried to verify standby power and I do get 5V in once place it's labeled. I figured if I can find something simple like a bad diode I'd fix it but since I have no use for the set anymore I don't want to put too much effort into it. I'll do a bit more searching before surrendering.

The plot thickens. I'm limited in what I can do with the main board hooked up (about 20 connectors) and with it out of the set I'm not sure if my live tests are valid. Anyway, I put it all back together, attempted power again and still dead of course. But I left it plugged in. About 20 minutes later I heard the power relay clicking and the LED flashing. I pushed the power button a few times and the set came on.

I'm guessing the defective standby power may eventually charge a filter cap to the point it can pull a relay in but in so doing the voltage droops again unless one happens to be hitting the power button at just the right moment when main power can take over. So it really must be something quite simple. Or not. We shall see. I've not been able to trace things enough to find fault but maybe I'll have better luck if I can track down a schematic.

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Given the age involved, I'd just change the electrolytic caps on the psu secondary and go over the soldering in the psu and line stage. The symptoms suggest a cap or a cracked joint.

-B

Sony Trinitron KV27TS20

Good news. Never did find a schematic but Googling I found a mention of a capacitor, C605. This is an electrolytic 22uF* rated at 250V. It didn't look bad but unsoldering it it does look a little bulged at the bottom. I didn't have anything like that laying around but figure a bigger cap in a PS section might be worth trying I temp wired a 680uF* / 200V and with that in the circuit the TV starts and behaves normally. So I need to find one closer in value if not the exact replacement.

I measure 140V across it. It's there even with the set is off so obviously standby related. I had no idea standby voltage was so high. I suppose it could be from the wrong value; without a schematic I don't know if it would do that. But that does indeed seem to be the source of the problem.

• microfarad of course. Can't get a mu on here.

Here's one for future use: ?

Sylvia.

If you were running Windows, you'd be able to get it from the Character Map applet. And if you can also enter it directly by pressing ALT+0181.

Thanks Sylvia but that's not reproducing correctly here (running Xnews on Windows XP). I tried using one and saw it wasn't going to work.

Hmm...that one may work. µ Thanks.

I'm not sure what one I tried (pasting in from elsewhere) but probably the same thing Sylvia was suggesting. I don't know if others see that one correctly but I didn't.