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FERNSEH · 17th May 2014, 10:50 pm

The QF80. The original FC31 selenium rectifier had been replaced by a silicon diode of the BY127 type. The replacement diode along with an additional series resistor were fitted on to a piece of tag strip. The resistor can be 21 to 25 ohms 7watt. A 0.001 mfd capacitor was connected across the diode to protect it from mains borne spikes.
The FC31 is a contact cooled rectifier. Best replaced. The RV10 uses an RM5 finned rectifier, it could well be OK. If the smoothed HT is 228 volts and the unsmoothed HT is 235V I'd leave the old style rectifier in place. Boost voltage measured at C63 is according to the R & T book is 590 volts.

DFWB.

17th May 2014, 10:50 pm	#5
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Kolster Brandes RV 10 (Crown) The QF80. The original FC31 selenium rectifier had been replaced by a silicon diode of the BY127 type. The replacement diode along with an additional series resistor were fitted on to a piece of tag strip. The resistor can be 21 to 25 ohms 7watt. A 0.001 mfd capacitor was connected across the diode to protect it from mains borne spikes. The FC31 is a contact cooled rectifier. Best replaced. The RV10 uses an RM5 finned rectifier, it could well be OK. If the smoothed HT is 228 volts and the unsmoothed HT is 235V I'd leave the old style rectifier in place. Boost voltage measured at C63 is according to the R & T book is 590 volts. DFWB.