Motor speed and Rangefinder adjustments for all models of teletypewriter-reperforator, and Bias adjustment for
TT-76/GGC are found in TM 11-5815-238-10.
If reperforator is equipped with a synchronous motor, motor speed adjustment not required.
Bias Potentiometer Adjustment for TT-76AIGGC and later models
Make the following adjustment only when equipment is operating in a neutral circuit, since bias
windings are not used for polar operation.
Set keyboard SEND LOCK switch to the SEND position and the SELECTOR SWITCH to position 3 (LOCAL
Shut off equipment - switches.
Loosen the strap across the BIAS TEST MA terminal on the power supply and terminal unit and move to up
Power switch on position.
Connect a Multimeter in series with the terminal post. Refer to Troubleshooting Table 2-2 Trouble No. 4
Loosen the locknut on the shaft of the bias potentiometer and turn the shaft with a screwdriver until a reading
of 8.75 mA is obtained for 20 mA operation or a reading of 12.25 mA is obtained for 60-mA operation.
Tighten the locknut and recheck the adjustment.
Turn off power switch.
Disconnect the multimeter and reconnect the strap between the BIAS TEST MA terminals.
Readjust the range. Refer to TM 11-5815-238-10.