11-11-2011, 06:53 PM
So,
Back to the MM.
The first job was to attempt to extract the stub of shaft from the Wavechange Switch knob.
This proved to be a complete non-event. I have been soaking it in Plusgas for days, so I nipped the end of the shaft gently in the vice and twisted the knob, which slid off with hardly any effort at all. Insert here a short interlude for swearing and a cup of tea. However, examination of the end of the shaft indicates that it's been cracked for some time, so perhaps it wasn't entirely my fault. The 'Volume' knob came off OK, probably because the shaft appears to be made of brass.
The next step then was to attempt to 'get at' the rest of the switch. I decided that it was going to be impractical to continue with the interconnecting wiring in place, so I had to document it all and disconnect. Actually some of it is so brittle - rubber insulation - that it will have to be replaced. Just in passing I checked the valve heaters when I took them out for safe storage and they're all OK.
This part of the radio - sorry Wireless - lives in an two compartment enclosure. The ends and the divider are Alloy castings. The Tuning Capacitor - two gang - is supported on the end castings as Col described. You can see the rear adjustable bearing in the middle of the cross in the second picture below.
I generally try to figure out how it was made, because that usually allows the process to be reversed. Logically you would expect that the whole block was assembled, added to the chassis and wired in. I'm sorry to say that it's not obvious to me. So, I'm going to ponder a bit more and talk to Col. Of course he hadn't got a digital camera when he did his - who had? - so I'm going to send him some pictures to jog his memory a bit more.
Finally I did have one small success. I managed to turn the shaft with a pair of pliers. Not very far, but enough to show that it isn't completely siezed. I'm very nervous about damaging the contact fingers so I'm being very careful. I've applied more Plusgas and left it soaking.
Alan
Back to the MM.
The first job was to attempt to extract the stub of shaft from the Wavechange Switch knob.
This proved to be a complete non-event. I have been soaking it in Plusgas for days, so I nipped the end of the shaft gently in the vice and twisted the knob, which slid off with hardly any effort at all. Insert here a short interlude for swearing and a cup of tea. However, examination of the end of the shaft indicates that it's been cracked for some time, so perhaps it wasn't entirely my fault. The 'Volume' knob came off OK, probably because the shaft appears to be made of brass.
The next step then was to attempt to 'get at' the rest of the switch. I decided that it was going to be impractical to continue with the interconnecting wiring in place, so I had to document it all and disconnect. Actually some of it is so brittle - rubber insulation - that it will have to be replaced. Just in passing I checked the valve heaters when I took them out for safe storage and they're all OK.
This part of the radio - sorry Wireless - lives in an two compartment enclosure. The ends and the divider are Alloy castings. The Tuning Capacitor - two gang - is supported on the end castings as Col described. You can see the rear adjustable bearing in the middle of the cross in the second picture below.
I generally try to figure out how it was made, because that usually allows the process to be reversed. Logically you would expect that the whole block was assembled, added to the chassis and wired in. I'm sorry to say that it's not obvious to me. So, I'm going to ponder a bit more and talk to Col. Of course he hadn't got a digital camera when he did his - who had? - so I'm going to send him some pictures to jog his memory a bit more.
Finally I did have one small success. I managed to turn the shaft with a pair of pliers. Not very far, but enough to show that it isn't completely siezed. I'm very nervous about damaging the contact fingers so I'm being very careful. I've applied more Plusgas and left it soaking.
Alan
