Fostex G24S Service Manual page 20

11) Adjust R300 (H) so that testpoint 1 wave length at maximum speed (winding the begin ­
ning of the tape in F. FWD or winding the end of the tape in RWD) is 0.65 msec. And confirm
that the difference of the maximum winding speed in F. FWD and in RWD should be within
0.03 msec.
12) Holding the |F. FWDj or [REWIND] button of the controller down.
13) Adjust R301 (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 SYSTE CONTROL PCB for a 50% duty of the test point 3 wave ­
form.
3) Adjust R305 on the SYSTE CONTROL PCB for a 50% duty of the test point 4 wave-
fonn.
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. 4.12, rotate R86
clockwise (CW), looking at it from the parts side of the DD CAPSTAN PCB, so that
duty is about 50%. If the waveform is opposite to that in Fig. 4.12, then rotate R86 for a
less than 50% waveform and R85 for a 50% duty.
Fig. 4.12
4) Repeat above step 3) until the duty remains at about 50% when SPEED is changed from
maximum through minimum.