UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Philips 663A combined radio/television 1948

FERNSEH · 27th Apr 2021, 8:38 pm

Doesn't the frequency changer employ two ECH35 triode-hexodes? The local oscillator is common to both vision and sound with the triode sections working together in a cross coupled arrangement.
I believe the pre-war model 2405 employed a similar circuit using ECH3 triode-hexodes.

DFWB.

27th Apr 2021, 8:38 pm	#10
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Philips 663A combined radio/television 1948 Doesn't the frequency changer employ two ECH35 triode-hexodes? The local oscillator is common to both vision and sound with the triode sections working together in a cross coupled arrangement. I believe the pre-war model 2405 employed a similar circuit using ECH3 triode-hexodes. DFWB.