Philips B2G04U (Techniek Radio/TV)

door Robert Gribnau , Konongo, Ghana, 22.04.2024, 23:15 (11 dagen geleden) @ DonaldStott

Hello Donald,

Links to Service Information for the B2G04U and the B2G81U.

Philips B2G04U

Philips B2G81U

Unfortunately, the dc-resistance of the primary is not stated in them.

But looking at the voltage drop over the primary (215 - 205 = 10 V), the 41 Ohm in the information you have, cannot be correct. The current needed to drop 10 V over 41 Ohm would have to be: I = V / R = 10 / 41 = 244 mA, which is way too high.

I cannot read what the cathode voltage of the UCL82 in the schematic is. But when looking at the Philips datasheets for the UCL82 and the ECL82 I think it should be 16.5 V, giving a cathode current of 42 mA. The anode current will then be around 35 mA. The dc-resistance of the primary would then be around: R = V / I = 10 / 0.035 = 350 Ohm.

I noted on the UK Vintage Radio Forum that you measured the dc-resistance of the primary to be 320 Ohm. To me that seems close enough.

--
Groet,
Robert