Bush TV24C

[Murphyv310]

Hi.

About 2 weeks ago I was talking to our Mr David Boynes, he told me about a TV24C on E-bay. I thought at the time he was keen on it but I took a look anyway. It had about 4 days to go and had two watchers. It looked tatty with no valves and a really dirty chassis and scratched cabinet but it was a £15 starting bid. I waited a couple of days and put in the bid. No one else bidded on it and I won. The TV was in Edinburgh and fortunately my sister was able to collect it as we were in Level 4 and travelling was out. She now lives alone as her husband passed in January so actually going was no real issue.
So we decided to go yesterday (Tuesday) for a visit anyway and for her to get better acquainted to Judy and of course for me to pick up the telly, this was the first decent run the Panda had since February too!

There was no valves in the set but other wise it was complete.
Today I got a look at it, I could only see one component that had been replaced and a re-gun CRT with a Pitrie label.
I've now removed the CRT and the two chassis, did my usual with TFR and pressure washed all the muck out of them. After they were given a good blast with hot air to dry and are now on the bench which has a 300 watt tubular heater underneath that makes the bench quite warm and the updraught of warm air chases out any further moisture.

I'm actually quite busy with some other things to do so the work on this will not be as fast as I'd like.
Here are some pictures.

[Murphyv310]

Some further pictures of the set etc.

[boater sam]

By 'eck, that's a lot of blood that's run out of that cabinet ! Looking a lot better now. How do you dry the LOPT out?

All the best to you and Judy.

[Murphyv310]

Hi Sam
Indeed there was a lot of blood ha ha.
The LOPT was given a good half hour with hot air, the chassis is sitting on the bench overnight with the warm air of the tubular heater. Then a couple of ma through the over wind for a few days.

All the best to you too Sam and your family.

[Murphyv310]

Hi.
Today I decided to give the set some power. First was to snip out the mains filter.
I then thought I'd check the LOPT and discovered the overwind was open. I had a sneaky feeling there could have been an issue here as the EHT lead was disconnected at the transformer and some odd botched wiring was on the EY51 tags. Well a rummage in the loft revealed a similar Bush transformer so I transplanted it onto the original transformer. Next was to slowly bring the set up on the variac. At around  140v AC the line burst into life, at 160v the EY51 was glowing and I had around 3kv of EHT. There was nothing on screen but grounding the CRT cathode and twiddling the ion trap brought up a white line. Increasing the AC to 160v the frame started.
That's as far as I've gone today so it's looking promising.

[ppppenguin]

Looks promising. I guess somebody just casually raided the vales from it.

[Murphyv310]

It was an interesting story.
The guy on ebay found it in a skip on a house clearance near where he stayed. Fortunately it obviously wasn't thrown in the skip and there was no damage.
I think the LOPT must have been the nail in the coffin for it but it was never thrown out at the time.
The under chassis is very clean and the CRT emission is really good. There was zero A1 volts due to a very leaky A1 decoupler, the reason only by grounding the CRT cathode gave me a raster.
The self oscillating line output doesn't always start but I'm sure once the usual components are replaced all should be well.

[peter scott]

Good progress! I like the CRT retention.

Peter

[Murphyv310]

Hi Peter.
I'm always wary of the TV24 as the bulb of the CRT just sits on the wooden cut out, if the only clamp round the gun assembly isn't tight enough the tube can slide forward and implode as the neck gets stressed.
The duck tape holds it securely when working on the set, although when recapping etc the tube is sat on the floor. The 12 inch tubes are considerably heavier than the 9 inch ones.

[Geordie McBoyne]

Yes, the method of mounting the CRT is decidedly dodgy. I remember many years ago noticing that fact when restoring a TV24 which was be to submitted as a topic on the vintage-radio forum. The TV24 didn't inspire many TV collectors to restore the set and the usual comment was it's a boring looking thing and best chopped up for parts to keep TV22s going. 
Twelve inch round CRT televisions with band 3 tuners are quite rare, the only notable model is the Pye VT2 and possibly the Ferguson 998T "Twelve Plus" although that set might have been converted by dealers.

The circuit diagram of the line timebase shows that the PL81 also operates as the oscillator. There might be a correct procedure setting up the line drive with trimmer TC1.  Perhaps it's that method where upon the trimmer is adjusted to produce a vertical kink line in the raster and then turned back slowly until the kink just disappears?

Geordie McBoyne.