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FERNSEH · 17th Jun 2018, 9:59 pm

"I have sent a copy of the service sheet that I have to the 3 addresses I received by PM."

Hi Tony, many thanks again for sending me the conversion information.

A brief description of the converter. A valve UHF tuner is connected to a two stage IF amplifier using EF183 and EF184 frame grid pentodes. An OA79 crystal diode detector feeds negative going video to the pentode section of a PCF80, the triode section functions as a cathode follower. A line flywheel discriminator is present on the converter unit and is used on both line standards. The two stage 6Mc/s FM sound amplifier uses an EF80 and the pentode section of a PCF80 V351B. The FM demodulator is an EB91 double-diode. The triode section of the PCF80 V351A is used a the DC amplifier in the line flywheel discriminator.
The converter valve heaters are connected into the existing heater chain. A 177ohm resistor is connected in parallel with the 31ohm heaters section of the mains dropper section R156 and the 172 ohm section R159 is shorted out.

DFWB.

17th Jun 2018, 9:59 pm	#11
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Ferguson 705T Phase II "I have sent a copy of the service sheet that I have to the 3 addresses I received by PM." Hi Tony, many thanks again for sending me the conversion information. A brief description of the converter. A valve UHF tuner is connected to a two stage IF amplifier using EF183 and EF184 frame grid pentodes. An OA79 crystal diode detector feeds negative going video to the pentode section of a PCF80, the triode section functions as a cathode follower. A line flywheel discriminator is present on the converter unit and is used on both line standards. The two stage 6Mc/s FM sound amplifier uses an EF80 and the pentode section of a PCF80 V351B. The FM demodulator is an EB91 double-diode. The triode section of the PCF80 V351A is used a the DC amplifier in the line flywheel discriminator. The converter valve heaters are connected into the existing heater chain. A 177ohm resistor is connected in parallel with the 31ohm heaters section of the mains dropper section R156 and the 172 ohm section R159 is shorted out. DFWB. Last edited by FERNSEH; 17th Jun 2018 at 10:11 pm.