Fostex G16 - Page 40

13) Adjust R30 1 (L) so that test point 1 wave length is 16 msec at the middle of the tape.
And confirm that the difference of the winding speed in F. FWD and in RWD should be
within 1 msec.
4.2.6.11 Adjusting the Reel Pulse Duty
1) Put transport in the F. FWD or RWD mode.
2) Adjust R304 on the SYSTEM CONTROL PCB for a 50% duty of the test point 3 wave
form.
3) Adjust R3O5 on the SYSTEM CONTROL PCB for a 50% duty of the test point 4 wave
form.
4.2.7 DD Capstan Servo Adjusting Procedure
4.2.7.1 Lock duty adjusting
1) Connect the oscilloscope probe to TP-2 on the DD CAPSTAN PCB.
2) Set transport in the PLAY mode and adjust R85 and R86 so that a square wave appears
at TP-2.
3) Switch ON the ¡ PITCH CONT button and while watching the waveform of TP-2 on the
oscilloscope, vary the SPEED by rotating the PITCH CONT KNOB from maximum
through minimum. If the square wave duty changes as shown in Fig. 4.11, rotate R86
clockwise (CW), looking at it from the component side of the DD CAPSTAN PCB, so that
duty is about 50%. If the waveform is opposite to that in Fig. 4.11, then rotate R86 for a
less than 50% waveform and R85 for a 50% duty.
maximum
minimum
Fig. 4.11
4) Repeat above step 3) until the duty remains at about 50% when SPEED is changed from
maximum through minimum.
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