View Full Version : Somebody might have an idea
Earlsays 03-08-2008, 11:19 PM Okay, so cruising around today, I see a big "drop off your old junk here" pile in a school parking lot...a bunch of TVs, computer monitors, misc. BPC etc.
So, I stop and look, hoping for a score...what do I see, but a 27" SONY WEGA flat tube TV...I've wanted one of these for a while now...it looks to be OK, some scratches on the top and sides of the outer case, but nothing major looking really...so I take it home, plug it into the wall, plug my LD player into it, load up a disc, and cross my fingers
Turn it on, I have video, I have audio and all is good!!
SCORE!!
I call a friend, talking about how cool this is, and how I NEVER run across deals like this...
then the TV shuts itself off. I hang up the phone.
The red standby light is flasing twice over and over and over again.
I turn it back on...I get audio for a second, then it clicks off, no time for video to turn on (or it just didn't, don't know)
So, I do this a few more times, unplugging, plugging in, etc. Same thing. When the TV would turn on, I would get five flashes of the red LED, and then a pause, then two flashes, and a pause, and two flashes over and over again.
Now the TV will click on, flash five times, click off, pause, two flashes, no audio, no video, nothing, the on/off happens real fast.
Any ideas? Obviously the tube itself is fine, the picture was real nice. Audio sounded good...really strange. And a bummer.
MRX37 03-08-2008, 11:23 PM Maybe a leaky cap somewhere in the TV. That's all I can think of.
mr_fixer 03-09-2008, 01:23 AM yeah it doesn't sound major, just a borderline faulty part. I wish i could tell you more, but some experienced tv guy could direct you better. Good luck in that , Logan
dr.ido 03-09-2008, 03:54 AM It could be a heat related fault (dry joint, etc). That would explain how it ran for a while before shutting down, but wouldn't start up again. Will it start up again if it is left to cool down completely?
If the horizontal driver transformer is dry jointed (a common fault in some Sony's, but I've yet to work on any of the WEGA series) it could have taken out the horizontal output transformer.
Earlsays 03-09-2008, 04:48 AM is the horizontal output transformer an expensive fix? I was reading that a problem on some of the WEGA tvs is that they have a transformer mounted on a board which cannot support the weight of the transformer sitting on the board, and the board cracks...600 doller repair in that case, which, isn't worth it...I'll probably just dump it back where I found it....well maybe...I hate to do that though...these throwaway electronics are truely sad...
RetroHacker 03-09-2008, 07:57 AM Just check for cold solder joints or board cracks. Even if the board is cracked and broken, it can still be repaired. Some glue will hold the board back together, then you can bridge across the cracks with bits of wire and solder. A support under the board will prevent it from breaking again.
I've not worked on a WEGA, so I don't know anything about it. But check for cold solder joints. They seem to plauge modern TV's. I think it was somewhere in the 80's where many TV manufaturers entirely forgot how to solder. Sony seemed to have it down until the mid 90's, then promplty forgot.
-Ian
dr.ido 03-09-2008, 11:59 AM Boards can crack around the flyback transformer especially if the set has been dropped. As RetroHacker said it is repairable. I've repaired several sets with cracked boards and it isn't a difficult job. I can't see anyone charging $600 for such a repair even when these sets were new and still worth money.
The standby LED blinking twice usually indicates that it is shutting down due to excessive current on the B+ rail. In such a case the first thing I would look for is a shorted horizontal output transistor (which is actually what I meant to type above when I typed horizontal output transformer, I need to proofread more).
Check the horizontal output transistor with a multimeter on the diode test range. If it reads shorted between the base and collector it is bad. Look up the part number on the various part supplier websites to get a price. I almost always use salvaged parts so I don't know what the going rate is.
Earlsays 03-10-2008, 05:34 AM Well, I'm going to take it to somebody...if it where a receiver, or power amp, or preamp, CD player, laserdisc, or anything like that, fine, I'd take it apart and give it a go...but I won't dissassemble a TV...I'm not about to get near anything that holds the kind of voltage a tube TV can hold...
RetroHacker 03-10-2008, 07:20 AM I'm not about to get near anything that holds the kind of voltage a tube TV can hold...
But that's a Sony WEGA. It's not a tube tv - it's solid state.
:D
-Ian
Earlsays 03-10-2008, 09:00 AM But that's a Sony WEGA. It's not a tube tv - it's solid state.
:D
-Ian
Oh geez...but, I just...you...uhhh.....ahhhh dammit :thmbsp::D
freakaftr8 03-10-2008, 10:04 AM But yes if you don't feel confident about it, taker it to somebody, even though it's solid state, the CRT holds a nasty voltage and can send you flying accross the room if you touch the wrong part..
MRX37 03-10-2008, 11:44 AM There should really only be high voltages in the large capacitors, and the HV wire that runs from the CRT to the flyback, but yeah, better to let somebody who works on the things give it a go. I've heard when those flyback wires bite, they bite hard...
It's easy to discharge, and you don't even need to do that unless you disconnect the HV wire from the CRT. While it's connected, it's very well insulated. The charge on the B+ caps in most stereo receivers is much more dangerous than the CRT in a TV.
ChrisW6ATV 03-10-2008, 01:19 PM This problem sounds very much like one or more bad caps in the power supply.
freakaftr8 03-10-2008, 06:05 PM True, if it was a short, it would have taken out the 1/2 ohm 1/4w fusistor.
(R604) i presume on the newer chassis
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