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is my tv irreparably damaged? audible pop heard

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 ksjs 16 May 2010
recently my quite old but still very good tv made a load pop and then went off; it wont do standby even and there are no signs of life. im assuming something like the cathode ray tube has broken and i guess this is uneconomic to repair.

anyone got any suggestions for what else it could be? also, if it was the cathode ray tube is this really too expensive to repair?

thanks
 jkarran 16 May 2010
In reply to ksjs:

Audible pops (usually accompanied by yellow acrid smoke and electrical failure) from older electronics are usually failed electrolytic capacitors. They're easy to identify (they're the black exploded ones), cheap and usually easy to replace.

Don't open the TV yourself unless you know what you're doing, it can hold enough charge to kill for days.

jk
 gethin_allen 16 May 2010
In reply to ksjs:
probably just a capacitor in the power supply.
Make sure the power is off and DO NOT TOUCH ANY OF THE CAPACITORS or anything at all if you don't know exactly what you are doing. Large capacitors can hold a massive charge that will give you quite a jolt if you discharge one.
If it's not under warranty and you are competent you could probably remove the back of it with a screwdriver and have a look for blown capacitors (the tops blow off when they pop so it's easily visible).
If you can see the problem you may be able to get it fixed or if you really know what you are doing and can get the parts you may be able to fix it your self.
banned profile 74 16 May 2010
In reply to ksjs: could just be a fuse
 Jim Fraser 16 May 2010
In reply to ksjs:

Capacitor and power supply makes sense. It could be other things but the power supply is definitely where I'd look first.
 smithy 16 May 2010
In reply to ksjs:

Friendly cats are good for discharging capacitors.

 gethin_allen 16 May 2010
In reply to smithy:
Some of the capacitors in the back of my old TV were as thick as my wrist and could probably kill a human so would probably turn a cat to dust.
 smithy 16 May 2010
In reply to gethin_allen:

And that solves the problem of disposing of a burnt cat without the neighbours realising what happened to their feline friend.
 David Riley 16 May 2010
In reply to ksjs:

My tv did the same 15 years ago. I took the back off, but could not find the fault, so carried it into the local repair shop. The owner asked why I had taken the back off and called me an idiot. So I walked out again.
I got Sony to send me a circuit diagram and found a power resistor had gone short circuit taking out a big switching transistor. When I replaced them both, about £3 worth, it was good as new. It still is.

I was dead lucky to find and fix the fault easily. Without a circuit diagram and a voltmeter I could not have done it. You are probably not going to be successful unless you can do the same.
I doubt the tube has gone.
 jon 16 May 2010
In reply to ksjs:

Probably a valve that's gone. Bin it and get a colour one.
 Blue Straggler 16 May 2010
In reply to ksjs:


Happened to my telly about 7 years ago. Took it to a small independent local repair shop, he diagnosed the problem instantly (very similar to what others are suggesting here) and fixed it for £30, and showed me what he'd done. It happened again in 2006 and I was able to fix it myself (I have some electronics ability/experience), just ordered a capacitor for about 35p, job done. Still going strong today, that telly - I bought it as an ex-rental from Radio Rentals in 1996 and it's moved house with me a ludicrous number of times. They are pretty tough, those big old tellies!
OP ksjs 17 May 2010
In reply to jkarran: no smoke but electrical failure
OP ksjs 17 May 2010
In reply to gethin_allen: its old but still great picture so i'll have a look
OP ksjs 17 May 2010
In reply to beastofackworth: tried this and no
OP ksjs 17 May 2010
In reply to Jim Fraser: could it be a combination of failed fuse and capacitor ie one causing the other?
OP ksjs 17 May 2010
In reply to David Riley: think i might get stuck with voltmeter and circuit diagram! will take back off and have a look and if i cant see anything obvious will take it to someone who knows what theyre doing. i really dont like binning stuff that with a small bit of effort is perfectly good...
OP ksjs 17 May 2010
In reply to jon: it is (was) colour
OP ksjs 17 May 2010
In reply to Blue Straggler: yep - im surprised this has lasted as long as it has: has moved house 3 times and been carted up and down stairs several times as part of 'making the room look as big as possible for house sale viewing' tactics; its a bit of a beast!

thanks all for replies - sounds like there may be hope yet...
In reply to ksjs:

As others have said, the most common fault that causes a pop is an electrolytic capacitor. Often the one in the power supply swithching regulator (a very common fault with Freeview boxes or supplies).

If you're lucky, you'll just have taken out the capacitor and fuse, but it may also have taken out the switching regulator. Sometimes, this explodes so violently that you can no longer identify it from the remains...

Caps often leak before they fail (which is why they fail), so look for residue around all the big-looking caps.

Also heed the warnings about residual voltages; a colour TV can have around 36kV in the back, which will give you a nasty shock. It should have a discharge circuit fitted to it.

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