Teac A-6100 Service Manual page 26

BIAS TRAP ADJUSTMENT
The following check and adjustments must be performed
with the EQ switch in the #1 position.
1. Place BIAS switch in #1 position, MONITOR switch in
TAPE position, and RECORD MODE switch to "ON".
Depress REC and PAUSE buttons.
2. Connect a VTVM or oscilloscope to the junction of
C-320/L-302 (Left channel), C-344/L-304 (Right channel).
3. Adjust L-302, L-304 for minimum reading.
Fig.11-4 Bias Trap Check Point and Adjustment Locations
BIAS ADJUSTMENT-
NOTE: Adjust bias traps (above) before proceeding. The following
adjustments are made only at 7-1/2 ips ( 19 cm ) tape speed.
The bias oscillator frequency is 100 kHz (±5 kHz).
RECORD BIAS switch #1 position
1. Thread record Test Tape YTT-8013 on the unit.
2. Place the REC BIAS switch to #1 and place the unit
in the record mode.
3. Place the MONITOR switch in the TAPE position.
4. Apply a 7 KHz signal at -18dB to the LINE IN jack.
5. While recording, adjust capacitor VC-401/402 for peak
recording on the Test Set. From the peak, turn the
capacitors clockwise until a decrease of 2.5 dB is
obtained.(N.B.: This will be slight overbias setting
as is usually preferred.)
Fig. 11-5 Bias Limits Chart
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