Sony KV-M1421U with no colour.

[Mikey405]

Hi everyone.

I'm not sure whether this (a 19 year old CTV) qualifies as "Vintage" television, so this may be in the wrong section, but here goes anyway.

I bought an old (aged 90) mate of mine a little Sony TV off ebay after his decrepit Mitusbishi portable set blew up last week. On collecting the set from Stourbridge and getting it home, it has a wonderful bright picture but... it's in black and white. I don't have a service manual for this set, but before I rush out and try and find a copy I wondered whether anyone has any immediate ideas as to what the problem could be. Ie. Whether there are any known faults. The colour returned for about 10 minutes after the set had been on for 1/2 an hour, but then went off again and has not been seen since. The set is tuned in correctly and the colour is also missing on composite video in using the scart socket. The 'text is still in colour obviously. No amount of percussive maintenance (banging the top of the set) seems to make any difference either.

Decoder faults are my favourite kind but does anyone have any immediate thoughts (or a scan of the service manual for that matter)?

Thanks everyone.

From Mike.

[Dr-Watts]

Check the crystal by replacement, old bean

Dave W

[Nickthedentist]

Chassis is BE-2A

I downloaded a free manual from "ESI" in Bulgaria (?) which I could send you, but it's 5.65MB so maybe too big for e-mail?

Nick.

[Nickthedentist]

Googling suggests trimmer CT332, which can be replaced with a fixed, 50pF ceramic cap instead

[Nickthedentist]

See also here under BE-2A:

http://www.highlandelectrix.fsnet.co...NY.TV.html#BE2

[Mikey405]

Wow. Thanks Dave and Nick. I'll certainly try those. 5.6MB isn't too big for email and a manual would be excellent. I don't think I'm allowed to put my email address up here(?) but it's on my web site anyway... Thank you Nick.

From Mike.

[Welsh Anorak]

Hi Mikey
It's the trimmer! I think it's actually 18pF - I use the one supplied by Sony (SEME stock it) or else the old style trimmer is stocked by Charles Hyde.
Of course, one drop of switch cleaner and a twiddle works for a while!

Glyn

[dsergeant]

I usually replace the trimmer with a fixed 18pf cap and never had any comebacks. That suggested 50pF is far too big!!

Note that a 5.6Mb file will become more like 10Mb when you email it because of the encoding. That is why it is far better to load it up to some web site somewhere or use things like yousendit which do not have the overhead.

Dave

[Studio263]

Certainly the trimmer, I took one with me on holiday to Zimbabwe to complete a highly impressive "field repair" on one of these sets, "how did you know?" they said, easy, it's never anything else...

A solder-up inside the IF can is a good idea too, especially around the pins of the "toko" type coils. Tuning drift and baffling AFC faults can result otherwise.

I also like to replace the diode that feeds the A1's in the tube while I'm at it, it lives down by the LOPT and seems to fail when the casing breaks down and the current tracks along it. This normally takes out a 1K resistor in series too. The symptoms of this sort of sillyness are not the blank screen that you would expect, it looks more like the tube is absolutely flat (not altogether unknown with Sony sets, though not these ones). I use 2 1N4007's in series, there is less chance of the tracking recurring then.

[Mikey405]

Thanks everyone for your help.

I took the TV out of my car this evening and plugged it in - and it had colour. Anyway, I removed the orange trimmer and replaced it with a 22pF fixed capacitor which was the nearest small size that I had. Anyway, the colour still works so it certainly hasn't done it any harm.

I think that this was a kitchen set judging by the amount of disgusting greasy grime that coated the whole set, and the strange smell of sage-and-onion stuffing that starts wafting out after the set has been on for 10 minutes.

Thanks again everyone.

From Mike.
PS. I don't suppose anyone has a remote control I could purchase for this set do they? The one that came with it is extremely battered and a couple of rows of buttons don't work. I think that an all-in-one won't work because of the combinations of buttons required to tune it in. Maybe I could tune it in with one remote and use the all-in-one for changing the channels. Hmm.

[Nickthedentist]

Originally Posted by Mikey405

I think that an all-in-one won't work because of the combinations of buttons required to tune it in. Maybe I could tune it in with one remote and use the all-in-one for changing the channels. Hmm.

That's what I'd do. Keep the battered original somewhere safe as a "service remote", and give a cheap, new, universal one to your friend for everyday use. One of the 5-button types (channel +/-, volume +/- and standby) would do the job.

BTW, did you receive the manual from me?

Nick.