Pye D16T

[Murphyv310]

Hi.
Both bases have now been replaced and rewired. Any surrounding components have been replaced as a matter of course.
Next thing is the problematical transformers. Getting there slowly but surely.

[Murphyv310]

Hi.
Well three hours of work has been very fruitful.
I have recapped the RF unit as best as I can. all the decouplers that are on the HT side have been replaced, heater and cathode decouplers have been left in the meantime. I have rewired all of the perished rubber cabling and replaced some electrolytic caps that were literally disintegrating with corrosion.
The 6 x 10m resistors in the EHT discharge network were either O/C or very high value so these will be replaced with 10x 6.8m which are rated at 1kv so plenty of margin there. I have also repaired the Frame output TX that had a broken connection. Sunday I will hopefully start to reform the HT caps.

[Murphyv310]

Hi.
Well the main smoothing caps were in a sorry mess I didn't realise they were so bad on the side that wasn't visible, one had eaten right through the alloy. So one brand new cap was fitted and two other NOS ones have been fitted. The 1.5k feed to the audio amp was O/C and has been replaced. I've now fitted the nine 6.8m resistors in the bleeder circuit. HT has been run up and is fine.

I hope that during the week I'll be able to power the set up and see what else needs to be done.
Pictures soon!!!

[ppppenguin]

This set does look as if it's suffered in storage. Quite a lot of rust. So not surprising that there are a lot of problems.

[Murphyv310]

Probably one of the worst I've done.
The 50uf across the focus coil disintegrated when I was removing its retaining clip.
The wax caps were the most leaky I've come across as well. Fortunately I've been able to drive out the moisture in the mains transformer, let's hope it stands up OK with full AC applied its OK at 180v and the full power supply will be sitting in warmth for a few more days.

[Murphyv310]

Hi.
Later this afternoon I fed the set with some power. I powered the main deck from the Labpack, both HT & LT. Both time bases burst into life with line and frame hold controls working as they should. Next was to test the RF unit. There was no video or sound this was traced to the first EF50 having open circuit heaters, we now have good video and audio.
The sync winding on the frame blocking transformer is O/C so needs to be repaired. I will though fire up the set on its own PSU and fit the CRT and see how it looks firstly.

[ppppenguin]

It's nice to run up an unknown set on a lab PSU. With a live chassis set I might run the heaters from an isolating TX and the HT from a lab PSU.

With a B/D16T there's no worry about live chassis. One of the reasons the BBC used them as (relatively) low cost video monitors in the 1940s and early 50s.

[Murphyv310]

Hi.
The big advantage using the Labpack is that there is no Mains EHT floating around when working on the chassis, that will come nearer the final testing with the CRT in place.
One silly mistake could mean curtains!!!!

[LENINGRAD T2]

Hi Trevor,
I have the impression that if someone told you: I only have a D16T housing and a MW22-7 CRT. Can you fix it? The answer would be - of course

[LENINGRAD T2]

Is the Invicta TL31 a copy of the D16T?