FAULT After switching on, the picture has a green hue. This disappears after a few minutes. Often, the picture is normal after switching on.
COMMENTS The TV is probably 12 to 14 years old, so we've had good use from it, but I was wondering whether this fault might lead to a complete failure in the future or further steady deterioration.
Also, does anyone (a TV engineer maybe) have a diagnosis for the fault described and know whether it would be worth repairing.
Degauss it? Either with a degaussing wand or cheat and get a TV / monitor with an inbuilt degaussing circuit (they make a sort of BWONGG noise when you turn them on), hold it against the screen and turn it on.
OTOH you can watch the BBC News without noticing the annoying way it turns green for a fraction of a second every so often...
Well, not really possible to say from the symptoms you've described.
But, :-)
If the picture gradually returns to normal as the set warms up it may indicate a low output red gun in the tube (which can't match the green), this would be consistent with the age of the set. A cure would be a replacement tube. Probably not economic or practical.
If the fault suddenly clears after a few minutes it could be a flaky component or soldered joint/bad connection. The component may or may not be cheap but diagnosing which one is defective is likely to take a lot of expensive time.
All in all the recommendation is get what use out of it you can whilst it is still serviceable.
BTW I don't think it's magnetised as MR Doki suggests. If the green hue is even over the whole screen, not causing "rainbow type fringes" this diagnosis may be regarded as definite.
Most likely an ageing thermistor on the degaussing coils which is heating up too slowly. Simple component to change costing about £1 - although being Sony that will probably be more like a tenner!
Can't see that myself, can you explain why a set that hasn't been moved or had any external magnetic fields applied since last use be cured by a degauss?
I go for an ageing component in the drive to the red gun or the red gun has just got tired. If the fault clears suddenly rather than slowly the set may respond to "impact maintenace" when it exhibits the fault. ie give the set a thump.
BTW -red actually makes the image cyan, -blue yellow, and -green magenta. If the fault really is green then it's either +green or -red and -blue...
Red gun probably going down. Not worth fixing since you can generally pick up S/H or ex rental TV's in good nick for less than teh ciost of getting a service engineer to take the back off.
12-14 years is about where tubes start to fail. Unless its top of the range, its not worth re-tubing frankly.
I wander into my TV service man occasionally, and generally find a stonking 17"-23" set for under 90 quid. Sonys are my favorites.
And about 50 quid to take the back off and resolder it on, plus the cost of taking it in to the repair center...
IF you have a good small bloke who fixes TV's like what Tony Sayer put me onto, wander in and have a chat. Cjhances are he will take a look, and say 'heres one I repaired earlier that you cvan have for 80 quid, and I'll take this one for spares, or fix it in my own time and sell it on if its worth it'.
For some reason, Sony seem far more prone to this than other makes - and always the red gun dying which produces 'green' pictures. But a grey scale re-balance once in a while can keep them going ok for many a year. I assume modern sets do this automagically.
Yeah we had an old Sony many years ago which had a green cast. A tv repair bod we knew said that they were notrious for it. Being poor we couldn't afford to replace it - actually as I recall colour tvs cost loads and loads relative to what they cost now - and so we put up with it and got used to it. It was odd when we went and watched other peoples tvs.
Unless the red gun had failed completely, it should have been possible to adjust it ok. Indeed, early Sony models had the controls for this on the back of the set, rather than buried inside as with most.
I've had my 17" Sony 'Monitor style' TV for at least 15 years now. Fine for the first 6 years then the on/off switch failed and I repaired it (not replaced notice) myself ;-)
Then the Teletext failed (years later) and I phoned my mate (with his TV repoair shop now gone) and he said C32 on the XYZ board. I changed it and all sorted again.
Some years later the HT transfomer went, he got me one and dropped it round, I removed the old one and my 12 year old daughter soldered it back in (If she can solder 80 LED's in on a Maplin project, 12 legs on an HT Transformer would be a doddle!) ;-)
For a while the colours have been going a bit weird .. the red would 'flare up' when there was a lot of red in the frame then settle back down again?
This morning I switched it on and about 2 mins later there was a bit of a HT type noise the picture broke up horizontally and it shut down. I left it off 5 mins and turned it back on (expecting it to be dead) and it seemed a bit 'grey' and switched itself off 20 mins later. Turned it back on and it's been on most of the day now and seems to be back to normal ?
We will have to see what it's like in the morning?
Each time my mate told me what it was over the phone I'd pop 10 or 20 quid into his shop when I next went past. Now he's gone I'm not sure what the future will bring for the little Sony ;-(
This is a familiar fault and usually easily cured. Its most likely a tube with falling emission on red gun, or less tube with short on green gun. It could be other things but emission is usually what causes it.
In which case the set should run fine for a fair while, apart from the initial greening. Over time it can be expected to very slowly deteriorate, with warm up taking longer, and in time the picture would stay a bit tinted, and in some years time you'd get a funny colour to the picture all the time.
If youre sure the pics fine once its warmed up - try it on the test card and check the grey scale really is OK, all greys no green. Knowing what colour each portion of the grey scale has gone is useful.
Its normally the tube. Most people go into stupid mode once theres a tube fault, but in reality tube emission is simple to fix. All it takes is applying a higher V to the tube heater, and magically the problem vanishes for the next 5 years or longer. This can be done by looking at the heater power circuit and tweaking it. If its run off a few turns on the LOPTF then add another turn round the outside, using well insulated wire. If its run from a regulated supply, connecting to before the regulator usually gives about the right boost, etc.
Tube emission faults are really not hard to fix if you can solder and understand the dangers inherent in any TV, and act sensibly around them.
Do I know what I'm talking about on this? Yup.
For legal reasons, dont do anything. I say this because if you dont understand the dangers and act with sense around them, you could risk getting electrocuted.
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