Pye D16T

[Murphyv310]

Absolutely Jeffrey. I need a rest from it right now. Clearing the shed of fallout right now.

[LENINGRAD T2]

If you are tired, it's best to change your surroundings. You have to send the D16T around the earth and take care of something less humid. .

[Murphyv310]

Hi Adam.
I have to say that to cap it all I wasn't feeling on top form today which didn't help. I've put out a wanted on the UKVRRR forum and hope I get some responses, another chassis could be useful to get. In the next few days I will remove the line scan transformer and warm it up and see if I can extract the actual transformer from the can. The other good news in a box I had of old valve bases in the loft when I was putting things away I found one PYE EF50 base that is the same as the one in the D16T so all might not be lost assuming the others hold up. I'll still keep the request open for parts though.
I think we will get the set going eventually but out of the time scale I initially thought.

[Murphyv310]

Hi.
Well the D16T is back on the bench. I've opened up the Line Scan Transformer can and found a problem with the wiring. This is odd as I thought it was potted but in fact no, its covered in a cardboard composition that was hard and brittle, the smoke was from a small bad joint that nearly caught the cardboard on fire....... one to watch. This has now been repaired and sealed.
Next was to look at the couple of sliders that were faulty, one was badly contaminated with a build up of dust and debris I have cleared all of this and I thought I'd try and lubricate them, I have some lanolin grease and this is allegedly good for electrical contacts so I gave them a light smear, the controls now feel very smooth and are giving a nice noise free operation, so that is good progress.
The Focus control though could be faulty but unfortunately I am not in a position to properly test how it is working as the CRT is now so low even with the lights off and window blind shut It's so dark and even a tiny amount of brightness the picture inverts. I might try the safe boost process and see if I can get some more emission, I do think the issue is the CRT is gassy and getting worse. I cannot test this with the MW6-2 as they need their own focus coils.
My own MW22-17 in the TV22 is poor as well and doesn't focus very well so not really suitable for a test. There is no 9 inch tubes at my late friends in Sorn, I suppose I could borrow a CRT from one of the sets in the museum though.
Tomorrow I'll do the frame blocking oscillator transformer swap and see what transpires there.

[Murphyv310]

Hi.
Tomorrow or Friday I intend to Test the set with the MW6-2 in the lash up I have used before, If all works as I hope it will I'll get a loan of a set with a 9 inch tube and do a proper test. There is a 9 inch Viewmaster there. There is also a 7BP7 radar tube that may be a better test if the Viewmaster CRT has gone down as it's been off for a good number of years.
Overall I'm hopeful of a decent result.
Watch this space.

[Murphyv310]

Hi.
The replacement blocking osc TX will be fitted today. All controls are now operative and this weekend I'll get the 7BP7 for a full test. Hoping this will be the end of the saga.

[Murphyv310]

Hi.
The saga is now over. Yesterday I got my 7BP7 back after many years. It was the basis of a CRT for testing the Pye. Once fitted there still the issue of way out frame speed. This tuned out to be a new 0.022uf cap reading 700pf!!! Once this was fitted we have the correct frame speed and locked as well.
The issue though is bad focus, the voltage across the focus coil is correct but the focus is not good.
I think its due to the parameters of the radar CRT requiring a different magnetic flux for good focus, any time I've used these tubes for tests the with a permanent magnet focus the control is in a totally different position.
The set has been running for a couple of hours now with so far no further problems. It will be run tomorrow all day for a soak test.

https://youtu.be/K-LV9iKEZPI