Ampex 440C 1" 8trk Capstan motor

[Echoplex]

I have a 400c 1" 8trk I've restored, clean, touch ups, new electrolytic's in the channel cards, transport, power supply motor caps etc. I have the DC motor with this deck and it is my understanding the C models only came with AC capstan servo motors. So that is confusing. My question is on the roll around under the transport by the fan (left side) there is a factory sub chassis (steel yellow zinc plate) about 3x5x5" with a small transformer on the outside and one Cinch cable that comes out of the box and goes into the transport. The sub chassis has access pots you can adjust. Any ideas? Is that anything to do with the AC Servo Capstan? I can't find a part number or description in my 440c manual. I'll try and get a picture

 

[Echoplex]

 

[sweetbeats]

No such thing as an AC servo capstan…it’s AC hysteresis sync.

The AC motor was an option on the 440C. The DC servo capstan was standard.

That box I think is the servo power supply but I’m not sure.

 

[sweetbeats]

The box may also be the servo assembly with the power supply. To what socket on the control box does it connect?