15-08-2015, 09:26 AM
Hi Trevor,
I haven't got a precise date for this set, however the very similar models in the radio servicing book are the 65A, 67A and P22B. Release dates: 65A, 1946; 67A, 1947; P22B, 1949.
Models 65A, P22B and 69B employ Mazda valves with Mazda Octal bases. The 67A uses Mullard valves, KCF30, KF35, KBC32 and KLL32 which have international octal bases.
I will have to make a mains power pack for the set. Once again I will use my favourite device, a mains transformer removed from a video recorder. There are plenty windings on these transformers and the winding for the fluorescent display can if wired in series other windings supply the 120V HT.
An LM317 regulator is used to supply 2 volts to light the valve filaments.
The first component to check is the phase splitter transformer which supplies the grids of the QP25 QPP double pentode output valve.
Geordie McBoyne.
I haven't got a precise date for this set, however the very similar models in the radio servicing book are the 65A, 67A and P22B. Release dates: 65A, 1946; 67A, 1947; P22B, 1949.
Models 65A, P22B and 69B employ Mazda valves with Mazda Octal bases. The 67A uses Mullard valves, KCF30, KF35, KBC32 and KLL32 which have international octal bases.
I will have to make a mains power pack for the set. Once again I will use my favourite device, a mains transformer removed from a video recorder. There are plenty windings on these transformers and the winding for the fluorescent display can if wired in series other windings supply the 120V HT.
An LM317 regulator is used to supply 2 volts to light the valve filaments.
The first component to check is the phase splitter transformer which supplies the grids of the QP25 QPP double pentode output valve.
Geordie McBoyne.
