by Rob-NYC »
Wed Feb 06, 2013 2:28 pm
Jon, I have an I-200 Mechanical selection. These machines have relatively weak gripper motors and plugs on those motors are prone to falling off.
Normally if the gripper motor has jammed due to overtravel it will blow the fuse. However that is dependent upon the pin not being reset. If the pin were to reset just a bit late the motor will still overtravel and jam but current will be cut before the fuse blows. This arrangement was a bit of a pain, that is why AMI went to a non-reversing AC motor in the K series.
Others here have given good advice, I'll add two points: You have to disconnect at least one lead from the trip switch to properly test it -though if the amp is muting that will not be the problem here.
Next, remove the little cover on the gripper motor's magnet structure and with power off, try to turn the armature with your finger. It will be easy to determine if the motor jammed. once you get it to turn manually, apply power and see if it 'takes off" and finishes the cycle. it is possible that the motor has developed an open turn on the armature or just poor brush contact. You can check for the roughly 28VDC at the motor's terminals using a multimeter, or just get a small 28 volt bulb, solder thin wires to it and stick those into the motor plug.
Has the power supply been rebuilt?
Rob/NYC
"If we believe absurdities, we shall commit atrocities" -- Voltaire