UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Ferguson 306T- EHT fade out

Focus Diode · 28th May 2007, 4:30 pm

I have one of these 1957 Ferguson 17" beauties. It works well after replacing the usual capacitors and the likes but there's one problem.

All is OK on warm up. After a few minutes however the EHT starts to fade with the usual symptoms, the height increases as the width narrows, becomes defocused etc. This gets progressively worse until hardly anything can be seen on the screen.

The usual troublesome decoupling capacitor known to cause this fault has been replaced, as have the valves including the PY32 HT Rectifier. I suspect the EHT overwind on the LOPT but is there anything else I may have missed?

Cheers,
Brian

28th May 2007, 4:30 pm	#1
Focus Diode Octode Join Date: Jan 2006 Location: Borough of Gateshead, UK. Posts: 1,420	Ferguson 306T- EHT fade out I have one of these 1957 Ferguson 17" beauties. It works well after replacing the usual capacitors and the likes but there's one problem. All is OK on warm up. After a few minutes however the EHT starts to fade with the usual symptoms, the height increases as the width narrows, becomes defocused etc. This gets progressively worse until hardly anything can be seen on the screen. The usual troublesome decoupling capacitor known to cause this fault has been replaced, as have the valves including the PY32 HT Rectifier. I suspect the EHT overwind on the LOPT but is there anything else I may have missed? Cheers, Brian