Section 3. Mechanical Adjustments; Section 4. Electrical Adjustments - Sony LBT-A57CD Service Manual

TC-D507
SECTION 3
MECHANICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcoholmois-
tened swab;
record/playback/erase head
pinch roller rubber belts
capstan idler
2. Demagnetize the record/playback head with a head demag-
netizer.
(Head demagnetizer do not approach for the erase head.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to
the parts adjusted.
5, The adjustments should be performed in the rated power
supply voltage unless otherwise noted.
Torque Measurement
Torque Torque meter Meter reading
FWD cao2c (08 to 08802 Inch)
Back tension CQ1026 (0.08 to 0.08 or inch)
REY. CO:102RE: (0.49 to 08 oe" Inch)
Back tension CO WARE (008 to 068 or nch)
FF, REW cQzo1n (ose te 12 Sa = Inch)
SECTION 4
ELECTRICAL ADJUSTMENTS
Note: The adjustment should be performed in the
order given in the service manual.-As a rule,
adjustment about playback should be per-
formed before adjustment about recording.
The adjustments should be performed for both
L-CH and R-CH.
@ Test Mode
The Test mode is acrivated by shorting Test Poing Service
mode (C801 64 pin changes over to "L" ) with
the POWER switch in OFF position, then turning on the
POWER switch.
In this mode, the following functions operate:
1, Source monitor
Line mute is cancelled during recording.
High speed playback
High speed playback is executed when the HIGH SPEED
(DUBBING) button is jpressed during playback. Normal
speed playback is restored when the button is pressed
again.
. Record memory
The tape counter is reset to "0" at the record start point.
After adjustment, open the Service mode to cancel the
Test mode.
2.
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[MAIN BOARD] (CONDUCTOR SIDE)