15-06-2020, 08:11 PM
Thanks Mike & Ed. 
Pencil inscription found inside case by possible first owner, dates set to no later than September 1941, whoever owned the set kept a record of dates of, (I believe), battery replacement up to the early 1950's!
Tuning is by friction drive.
Definitely octals, bases are paxolin and riveted, if they were retrofit then they were done very neatly indeed.
MW aerial loop and external aerial coupling on case back separate. Looking at the back of the set, two wires join the frame on the back lower left, external aerial connection is through sixth cutout hole on the top right. Other coil inside back of main case. Style of VC, (yes variable capacitor!) doesn't look same as pictures of contemporary sets. It is a Polar brand component....
Sorry can't do photo at present....
I think what has happened is that the VC has been replaced, and the minimum capacity is different to the original, the repairer has then messed with the loops and adjustments to compensate, or something. Ignoring the fact that the Local Oscillator is the main factor?
All that I can say for sure is that my tests have shown that the set has correct alignment of the IF (452khz) as per trader sheet.
I'm aware that the battery pack would have to be present in the radio for initial alignment when made.
The only work I've done is replace the grid coupling capacitor on the 1C5, the tone correction capacitor, 1C5 anode to LT- and the 8uF decoupling capacitor.
The set works on repro battery but frequency coverage and alignment complete pants! But where it works it does very well.
Ed....thanks for the offer....if I can get or work out details of the original loops then I would have a better idea of quantity and type of wire, I think the original was cotton served litz (?) I'll let you know
I have got some spare Mullard equivalent valves for replacements should they ever be needed, but the radios use will only be occasional, so I'd probably just use it as intended as a, (very heavy!) Portable.
Just as a reminder I can get myself unstuck with this if I know the inductance of the two main loops out of the case* and the maximum value of the tuning capacitor.
Amie.
Pencil inscription found inside case by possible first owner, dates set to no later than September 1941, whoever owned the set kept a record of dates of, (I believe), battery replacement up to the early 1950's!
Tuning is by friction drive.
Definitely octals, bases are paxolin and riveted, if they were retrofit then they were done very neatly indeed.
MW aerial loop and external aerial coupling on case back separate. Looking at the back of the set, two wires join the frame on the back lower left, external aerial connection is through sixth cutout hole on the top right. Other coil inside back of main case. Style of VC, (yes variable capacitor!) doesn't look same as pictures of contemporary sets. It is a Polar brand component....
Sorry can't do photo at present....
I think what has happened is that the VC has been replaced, and the minimum capacity is different to the original, the repairer has then messed with the loops and adjustments to compensate, or something. Ignoring the fact that the Local Oscillator is the main factor?
All that I can say for sure is that my tests have shown that the set has correct alignment of the IF (452khz) as per trader sheet.
I'm aware that the battery pack would have to be present in the radio for initial alignment when made.
The only work I've done is replace the grid coupling capacitor on the 1C5, the tone correction capacitor, 1C5 anode to LT- and the 8uF decoupling capacitor.
The set works on repro battery but frequency coverage and alignment complete pants! But where it works it does very well.
Ed....thanks for the offer....if I can get or work out details of the original loops then I would have a better idea of quantity and type of wire, I think the original was cotton served litz (?) I'll let you know
I have got some spare Mullard equivalent valves for replacements should they ever be needed, but the radios use will only be occasional, so I'd probably just use it as intended as a, (very heavy!) Portable.
Just as a reminder I can get myself unstuck with this if I know the inductance of the two main loops out of the case* and the maximum value of the tuning capacitor.
Amie.
