Peto Scott TV169 Restoration.

[peter scott]

A very tricky repair and a great result!

Peter

[`FRANK.C]

Great result Trevor.
An external multiplier was a good back up plan.

Frank

[Geordie McBoyne]

Hi Trevor, Absolutely perfect. The results are well worth all the effort you put into the job.

Geordie McBoyne.

[LENINGRAD T2]

Hi Trevor,

Peto Scott TV is an interesting copy from a historical and collector's point of view. I'm glad you launched the EHT unit in the spirit of the 50's, without excessive modernist solutions, especially on the outside. By the way, designing a compact 25KV box 70 years ago was a big challenge.

[Murphyv310]

Hi Adam.
Yes it was indeed a big challenge for that time. I have to say that I really thought I'd have to come up with another solution. Glad I didn't to be fair.
Next week I will progress with the rest of the set.
I'm having a weekend off fixing things to clear my head.
The weather is good, so tomorrow I'll be relaxing outside hopefully enjoying the sunshine.

[Murphyv310]

Hi.
Today I got some time on the Peto Scott. I have restuffed a few caps and those on the group board I'll just colour the yellow ones as the board is awkward to work on.
Some of the valve bases are not so good as they seem very cheap and the connections are poor, these will need to be replaced, I have only a few in stock so will need to order them.
Unusually this set does not have CRT protection, it also has a brightness fault which could be a man made issues as I think a cap has been fitted instead of a resistor that has been done many years ago.
I wonder if the lack of CRT protection is the reason these sets are now rare due to CRT failures and the cost of repair.

https://youtu.be/pFuJ-SG8QeI

[Murphyv310]

Some more progress today.
I was wrong there is CRT protection but its been bypassed no doubt due to a short circuit capacitor 0.1uf that I found. Protection now working and no frame sync sorted, due to very leaky 1nf sync decoupler. Picture very good indeed so just the decouplers in the tuned circuits and valve bases to attend to.
The video amplifier anode load is 2x 47k down to 5k the old body tip spot types. This gave no brightness once the protection was fixed, again I think the 1950s bodger was stuck with the fault.

[BusyBee]

You are working well through this Trevor. It sounds like much of the interest (and frustration) is working your way through the various faults that have been created by someone in the past. It's seldom I have that as I have not done much with TV's and seldom work with old radio's either. Perhaps I need to clear some space for a TV but that would not be easy in my little space.

Tracy

[Murphyv310]

Hi.
Most of the components that were faulty have now been replaced. All of the waxed paper caps were leaky, some badly and two with shorts, one of which I'm sure was the original fault.
There are two issues that may be related to sort out. The IF's have been twiddled and the alignment is awful, the cores are all mangled, there is some cogging too that I don't think is caused by the sync separator as the sync is good with no video content. Extricating the cores will be fun..... I doubt, but this has to be done, afterward I'll re align the set with the wobbulator.

I will need to get the CRT back in the Schmitt optics ASAP as I've been running the CRT hard out of the box so no doubt Its been emitting soft X-rays.

[Murphyv310]

Hi.
After a very long slog with this the work is now complete. The last few days I've been very busy with it as I need to clear the shed for a big amp that is heading this way next week.
The cores came out fine after a bit of warmth from the bottom. This set is for Channel two and its gain and lack of full bandwidth makes me think its a fringe model. Although its bright enough and gives a reasonable picture its not up to the standard of a Decca projection set.
Overall I'm hgappy enough with it though. The cogging is not seen on the Aurora although cogging is not seen on my other sets with the Hedghog, it may be due to the inbuilt test card as program material is fine. The soak test went fine and I'll be boxing the set up today.

https://youtu.be/XMJllI2xidA