Notifications
Clear all

Sony KV1320UB. restoration.

 
malcscott
(@malcscott)
Noble V-Ratter Registered
Posts: 1493

Hi, i have been given one of these very early Sony sets to restore for a friend. The crt is good but there are a few problems. The pic decreases in size as if the ht is dropping, poor frame sync. Before i make a start has anyone ever restored one of these. The last one i serviced was about 46 years ago! Malc.

ReplyQuote
Topic starter Posted : 10/06/2019 9:47 am
PYE625
(@pye625)
Famed V-Ratter Registered
Posts: 4980

Hi, I obtained one of these last year, here is a link to it...

https://www.radios-tv.co.uk/community/colour-television/sony-kv-1320-mkii/

Within my thread, you will find a link to UKVRR where there are some excellent tips on servicing.

I would hazard a guess that many problems can be attributed to tired and leaky electrolytics. I would be careful about running the set for too long with the fault you describe because if a transistor should fail, all sorts of cans of worms may be opened. ? 

 

ReplyQuote
Posted : 11/06/2019 9:02 pm
malcscott liked
hamid_1
(@hamid_1)
Active V-Ratter Registered
Posts: 226

Take note that there are two distinctly different versions of the KV-1320UB. There's the original version (serial number less than 100,000) often referred to as Mk.1 but not marked as such,  and the Mk.II version (serial number greater than 100,000) which usually says MK II on the front panel, beneath the rotary tuner.

The earlier version has a linear power supply with a heavy transformer in one corner, and a valve EHT rectifier. Despite the "Live Chassis" warning sticker, this version is isolated from the mains by virtue of the transformer. The Mk. II uses a switching power supply which is not isolated and can self-destruct if you're unlucky, taking out semiconductors which are hard to find replacements for. There are other circuit differences between the versions - be sure to obtain the correct service manual.

I've ended up with 3 of these sets, the first was a Mk.1 from the NVCF several years ago. This one powered up but had horizontal streaks on the picture. The fault was due to an electrolytic capacitor (something like 10uf 250v) on the power supply which provided the smoothed voltage for the RGB output stage. The capacitor had been leaking and one of its terminals had corroded away. A few other electrolytics looked a bit distressed and were changed too. Then another fault became apparent - black lines (noise) on the picture after a few minutes. This was eventually fixed by studio263 on the UKVRR forum. Cause: faulty small signal transistors. They had developed a black corrosion on their pins which had eventually gone inside and ruined them. BC548 / BC558 types were used as replacements.

I've since been given a MkII which worked, but had a purple tint to the picture. I improved it by adjusting the RGB drive pots, but the tube is a bit tired. And another Mk1, this also has noise on the picture. I suspect it's the corroded transistor fault again though I haven't tried to fix this one yet. There are more than 70 transistors that could need changing ...

So far, electrolytic capacitors and transistors seem to have been the only faulty components I've come across, but I may have been lucky. Hope that helps.

ReplyQuote
Posted : 12/06/2019 7:46 pm
malcscott and PYE625 liked
PYE625
(@pye625)
Famed V-Ratter Registered
Posts: 4980

Important info there above by Hamid.... especially as I had automatically assumed it to be the mkII version for some reason.

ReplyQuote
Posted : 12/06/2019 10:06 pm
malcscott
(@malcscott)
Noble V-Ratter Registered
Posts: 1493

Hi, many thanks for the info. The serial number is 025296 so i need a manual for the early version.

ReplyQuote
Topic starter Posted : 13/06/2019 11:35 am