Conn 12 wheel schematic and mod ideas Options

[csoundso]

Hello all! I would like to make a replacement for the frequency generator (lower unit) of an old 12 wheel Conn Strobe tuner. There is not a model # on it and it is serial #52. Has a sloped glass cover in front of the wheels (about 45 degrees) instead of the straight front I have seen on other units. I know the original generator was based on an a driven tuning fork with sliding weights ( and flux capacitors I think). I hope to throw out everything but the motor, disks and geartrain, and U shaped tube (neon?). Anyhow, schematics and ideas would be most welcome. Mabey one of you has done this already? Also, anyone know about the wheel to wheel intonation error on this unit? I know that since semitones are related by an irrational number and you have a limited number of gear teeth to work with, that the designers must have had to swallow some error in the relative speed of the wheels. Wonder how much this is ? Thanks loads in advance!! Rob

[John Norris]

Hello all! I would like to make a replacement for the frequency generator (lower unit) of an old 12 wheel Conn Strobe tuner.

Whatever you replace it with will need to be able to provide 110V of power at 1/2 amp (approx.) to drive the motor.

There is not a model # on it and it is serial #52. Has a sloped glass cover in front of the wheels (about 45 degrees) instead of the straight front I have seen on other units.

Sounds like one of the old units from the 1930's. Does it have a wooden case?

I hope to throw out everything but the motor, disks and geartrain, and U shaped tube (neon?).

Hmmm...why?

Also, anyone know about the wheel to wheel intonation error on this unit?.....Wonder how much this is ?

The overall error was just under a cent.

John N.

[csoundso]

Hi John and thanks so much for the quick and helpful response. The unit does have a wood case. The cover lifts off leaving the steel chassis attached to a shallow wood tray.I am guessing from your comments that the generator unit provided a stable, variable, substitute for 110 vac 60hz to run a syncronus motor that would otherwise have been run right off the line current. The gear train error kind of puts a limit on the intonation accuracy but I would still like to give it a try. Wonder if I can purchase a schematic for this beast? Again, thanks so much for your help and for providing this fascinating forum. Best to you and yours, Rob

[Tiziano]

Does anyone know the oscillator's ferquency of ST-11 an ST-12 please ? I would like to change this stage with one more recent I thank you very much in advance