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Old 15th May 2021, 10:47 am   #30
beery's Avatar
Join Date: Jun 2006
Location: Ware, Hertfordshire, UK.
Posts: 887
Default Re: Philips 663A combined radio/television 1948

Originally Posted by matspar View Post
Would anyone tend to agree here?! bit of an unusual one.
I hate to rain on your parade Matt, but I would be pretty sure that the line output transformer has shorted turns. I'd like to be proven wrong, but do be prepared to send off the transformer for rewinding. One might hope that it was all caused by the breaking down of heater supplies to the EHT doubling rectifiers, probably not that, but there is no harm in checking that with some silicon EHT diodes.

For the benefit of people who are not used to such early sets... Line collapse is a symptom that you won't see with a conventional combined line output and EHT transformer. We only see the symptom in this set because the rectifiers in the EHT voltage doubler do not have their heaters powered by the line output transformer. Mains EHT sets can also display line collapse, something I have unfortunately come across myself.

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