I have been reading through the 1MC manual and RCA did a very good job of not only explaining how the system works, but showing you where all of the electrical components are and what the major ones do to make the machine run. For instance, I now know that a timing motor and relay # K20-G (I think) allow the tubes to warm up for one minute and prevent the 1MC/7MC from being operated until that motor hits a contact and opens up the bypass relay. I also know which relays are for the the bridge reproducer, which operate the 1MC circuits, which operate the 7MC circuits, which are tied to Channel A amp and Channel B amp, etc. I can actually pin-point a specific item to repair, knowing that it will fix a certain unit. They even tell you which vacuum tubes produce the different alarm noises. Very cool stuff.
So, my plan of attack for the 1MC is as follows:
1. Remove, clean, test, and maybe repair vacuum tubes - glass tubes can be reglued at the base.
2. Focus efforts on Signal Generator #1 and Power Amp. A (top amp).
3. Replace all accesible resistors in above items.
4. Test and replace, as necessary, the ten 1-microfarad, 250V capacitors in Amp A - I recently purchased a used Heathkit capacitor tester for pretty cheap.
5. Replace the missing test buttons and meter on the control panel - these can be used to activate the different alarms when the signal generator is set to test mode.
6. Install working vacuum tubes.
7. Remove, strip, and repaint alarm contactor face plates/handles.
8. Install new screws and bolts into the alarm contactor face plates.
9. Once power is restored to the I.C. Switch Panel, turn it on and debug any other problems.
Long -term restoration would include restoring Sig. Gen. 2 and Amp. B as stated above (redundant systems), reconnecting any disconnected alarm contactors back into the 1MC (if we can gain access behind the unit), restoring the reproducer and switch box on the bridge and running new wires to those items on the bridge, and finding replacement parts for the 1MC mic box in the control room. Mainly, we just need a microphone to get it working again and the switch needs a little TLC.
Resistors are cheap and most of them are easily accessible for removal and repalcement. Many NOS (new old stock) vacuum tubes have been donated to the cause, as well. So, I don't think that it will cost us anything but time to get steps 1 through 8 completed - 9 may be a different story. If someone wants to tackle steps 7 and 8, knock yourself out. Just mark down where the wires were connected to the back of the contactors before disconnecting them and use the right color when you repaint said contactor.
