Pye 31 Televison picture problem

[Radio Tech]

Hi folks

I got hold of this set from Lee who kindly brought it up for me, I injected a signal from an arora to get test card, at first the picture that did appear was very much distorted at one side, just as if there was noise of some sort mixed in, I turned the set off and went back to it only now there is a raster and no picture, I haven't yet checked valves but I thought it maybe the video amp, the other thing was it had a pick up hum on the sound. I hope its not the dreaded tuner / IF unit.

Best wishes

Ken

[MALC SCOTT]

These sets have loads of wax caps in them. Replace the lot, Malc.

[FERNSEH]

Pye 31: It that the 16" CRT dual standard set which has the loudspeaker on the cabinet base?

DFWB.

[dazzlevision]

Yes.

On this chassis, the one contrast control is not a "high level" type, so when it is turned down to minimum, you will probably lose all sound and vision. Also check the positions of both the IF and main chassis system switches.

[dazzlevision]

I'd also try pushing in each of the six pushbuttons in turn, in case they are not all set up for one Band and line standard.

A quick meter check on the LT supplies would also be wise (12V and 14V)

[Restoration73]

It looks like all the caps have been replaced with reliable types. Check the system
switch, these can be the cause of problems.

[Hunts smoothing bomb]

Hi Ken,

That's Interesting as the set when last powered (At Mikey405s meet, April I think)
Produced for the first few minutes a pretty good picture until the caps started deteriorating under the voltage stress, the picture slowly degraded, distorted until sync became non existent.

I think by replacing one capacitor at a time and then powering back up after each replacement you will get there, by doing it this way rather than a blanket change you will be checking your own work and also you will be able to see the improvements gained as each stage begins to operate correctly.

Cheers

[dazzlevision]

Hello,

Perhaps I should make it clear that the picture of the chassis in post #5 is of my own Pye 31F TV! I had already replaced all the usual suspect paper dielectric capacitors with Mullard "mustard" Polyester C296 or RS Polypropylene dielectric types.

Ken, if you want to know which capacitor types and brands to replace, take a look at this thread:

https://www.vintage-radio.net/forum/...d.php?p=627374

If your 31F uses the same life expired types as mine, then you should be looking at the yellow (or possibly green) TCC Supamold and TCC Duomold, the all blue plastic (or half yellow, half blue) Dubilier and the red, or black or brown encapsulated Hunts types (all axial leaded). I don't think there were any wax dipped caps in my 31F, but there might be one or two in yours.

Regards,

Dazzlevision

[Radio Tech]

Thanks everyone for your thoughts and input to the thread, I will be setting myself a target to replace some of those caps, at the moment I have shelved the job as work bench has another set to look at a Murphy V204

Regards

Ken

[The teleman]

Hi , for a raster but no sound or picture fault ( blank white screen with radio break through on sound ) I have found that T2 on the I/f panel is the one to replace I think from memory it's a BF196
Chris

[Radio Tech]

Hi folks

Have decided to scrap the set now as I found that the tuner and its associated parts were not as expected, it would have been far too costly and chances are I would have not found a known good tuner unit.

Mods please remove this post

Regards

Ken