Fostex G24S Service Manual page 33

1) Input a lOKHz signal through a tone-burst generator (100 msec ON, 500 msec ~ 1 sec
OFF) and adjust the level of tone-burst signal for-50dBV at G24S/G16S output jack.
2) Route the signal at TP3 of R/P A P PCB Assy through a band pass filter (BPF) with the
comer frequencies at 20Hz and 200Hz and at least a 12dB/octave roll-off characteristics.
Then, route the output signal from BPF to an oscilloscope.
3) Put G24S/G16S in the REC mode.
4) Adjust two pots R211 and R212 to minimize the peak-to-peak signal level as shown in
Fig. 4.21.
* Note Fi S- 421
If the BPF is not available at your hand, the Dynamic Offset adjustment can still be pro ­
ceeded without BPF as follow.
Adjust two pots (R211&R212) so that the signal level on the oscilloscope at output 2 is
symmetrical with AC GND level as shown in Fig. 4.22.
Also please refer to Fig. 4.23 which shows the relationship between the pots (R211 &
R2 12) and rotating direction (CW & CCW).