Bizarre Sony Fault - UK Vintage Radio Repair and Restoration Discussion Forum

Colourstar · 4th May 2009, 1:16 pm

A friend of mine rang to say his Sony colour set was displaying a picture fault that sounded so bizarre I asked him to send me some photos. He described the picture as having gone sepia with 'black triangles' hanging down over the top of it!

He wasn't wrong either. They appear to be superimposed over the picture, so it can't be scan coils or timebase related (or can it?) so what on earth would cause this.

I'm not in a position to get access to the set at the moment, but I'd be interested to hear if anyone has seen anything like this before!?!

Steve J

Michael Maurice · 4th May 2009, 2:06 pm

One thing that caused all sorts of weird faults in early Sony's was the 33µF/160V (or were they 250V) capacitors in the HT supply. The tell tale sign is a load of gunge around their legs.

Also check the 200V smoothing capacitor which can do the same thing.

Please note that the 33µF can be found both in the power supply section and on the main timebase boards, change them all.

I dont know if this is much use to you but its worth a try.

murphyv310 · 4th May 2009, 6:12 pm

Quote:

Originally Posted by Michael Maurice

Also check the 200V smoothing capacitor which can do the same thing.
.

Thats the cap! 200v feed to the RGB outputs
Well worth doing the other HT caps as well though.
Cheers
Trevor

Heatercathodeshort · 4th May 2009, 6:52 pm

The black ink curtains. Yes its the cap! J.

Colourstar · 4th May 2009, 6:57 pm

Thanks for the replies. So it's a known fault! I will respond accordingly and report back- hopefully with a result!

Cheers chaps!

Steve J

4th May 2009, 1:16 pm	#1
Colourstar Octode Join Date: Feb 2006 Location: Ilkeston, Derbyshire, UK. Posts: 1,398	Bizarre Sony Fault A friend of mine rang to say his Sony colour set was displaying a picture fault that sounded so bizarre I asked him to send me some photos. He described the picture as having gone sepia with 'black triangles' hanging down over the top of it! He wasn't wrong either. They appear to be superimposed over the picture, so it can't be scan coils or timebase related (or can it?) so what on earth would cause this. I'm not in a position to get access to the set at the moment, but I'd be interested to hear if anyone has seen anything like this before!?! Steve J Attached Thumbnails

4th May 2009, 2:06 pm	#2
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,225	Re: Bizarre Sony Fault One thing that caused all sorts of weird faults in early Sony's was the 33µF/160V (or were they 250V) capacitors in the HT supply. The tell tale sign is a load of gunge around their legs. Also check the 200V smoothing capacitor which can do the same thing. Please note that the 33µF can be found both in the power supply section and on the main timebase boards, change them all. I dont know if this is much use to you but its worth a try.

4th May 2009, 6:52 pm	#4
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Bizarre Sony Fault The black ink curtains. Yes its the cap! J.

4th May 2009, 6:57 pm	#5
Colourstar Octode Join Date: Feb 2006 Location: Ilkeston, Derbyshire, UK. Posts: 1,398	Re: Bizarre Sony Fault Thanks for the replies. So it's a known fault! I will respond accordingly and report back- hopefully with a result! Cheers chaps! Steve J