Teac A-3300SX - Bias and Record Head Adjustments

RECORD PERFORMANCE
8-14 BIAS TRAP ADJUSTMENT
OUTPUTSW............ TAPE
RECORD MODE SW......... ON
BIAS and EQSW ............ 1
Select REC PAUSE mode
. Remove all input signals.
. Connect a VTVM or oscilloscope from ground to the
junction of L-302 and C-312 (L-ch) and from ground to
the junction of L-304 and C-330 (R-ch). See Fig. 8-7.
. Adjust L-302 (L-ch) and L-304 (R-ch) for minimum
reading on scope or VT VM.
Use Plastic alignment tool.
Test Points
ON REC METER AMPL.
T-669
Fig. 8-7 Bias Trap Test Point
8-15 RECORD HEAD AZIMUTH ADJ.
NOTE:
Tape SPEED SW........... LOW
The effect of turning the azimuth screw will reg-
ister on the VTVM. A slight delay will be noticed.
Therefore, the screw must be rotated slightly with
a pause to see the effect.
— FINE ADJUSTMENT —
4.
Connect a VTVM to the OUTPUT jack and an AF
oscillator to the LINE IN jack.
Set the oscillator to 10 kHz at —18 dB (97 mV).
. Begin recording (Depress REC and PLAY buttons).
. While recording, adjust the azimuth screw for maximum
reading on the VTVM.
NOTE: It is absolutely essential to accomplish the above
da
8.
adjustment before performing the following adj. to
avoid phase errors greater than 45°.
Sweep the signal from 40 Hz to 16 kHz for 7-1/2 ips
speed (or 40 Hz to 10 kHz for 3-3/4 ips speed) and adjust
the azimuth so all signal are within 45° between channels.
Secure the screw with insulating locking paint.
OSCILLOSCOPE
OSCILLATOR fo?
(L) OUTPUT
T-62!
Fig. 8-8 Test Connection for Recording Check
8-16 BIAS ADJUSTMENT
Be sure the Bias Trap have been adjusted per section 8-14
before proceeding.
9.
10.
Tape SPEEDSW........... LOW
BIAS and EQ SW
Apply 7 kHz signal at —18 dB (97 mV) to the LINE IN
jacks.
While recording on the YTT-8003 Test Tape, adjust ca-
pacitor VC-401/VC-403 for peak reading on the VTVM,
then turn the capacitor clockwise until a decrease of 3
dB from the peak is obtained. (2 dB for 2T at
7-1/2 ips speed)
BIAS and EQ SW
. Apply 400 Hz signal at —8 dB (308 mV) to the LINE
IN jacks.
. While recording on the YTT-8023 Test Tape, adjust ca-
pacitor VC-402/VC-404 for peak Bias.
Peak Bias
OUTPUT LEVEL (dB)O
BIAS CURRENT (mA)
Fig. 8-9 Bias Limits Chart