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Old 4th Aug 2016, 2:41 pm   #31
Heatercathodeshort
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Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 7,612
Default Re: 1948/1949 Philips type 520A television and radio

The first Philips television manufactured after the war as far as I know is the series with voltage doubler HVR2 rectifiers developing EHT from the pulse available on the anode of the line output valve. No EHT mains transformer was employed despite the chassis containing several large transformers and HVR2 rectifiers.
The first true flyback models had an oil filled transformer[?] and two EY51 EHT rectifiers again in a voltage doubler circuit. Their heaters were powered from the flyback transformer unlike the early model that had the two HVR2 rectifier heaters powered from a specially insulated mains transformer.
It would appear that the 520 was sandwiched between the 385/485 series and the 1100, a truly incredibly reliable receiver. Maybe I'm wrong. John.
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