Electrical Adjustments - Sony TC-KB820S Service Manual

Note: The adjustment should be performed in the order given in the ser-
vice manual. As a rule, adjustments about playback should be per-
formed before those about recording.
The adjustments should be performed before for both L-CH and R-
CH.
• Switches and controls should be set as follows unless otherwise
specified.
DOLBY NR, MPX FILTER switch : OFF
• Standard Record:
Deliver the standard input signal level to the input jack and set
the REC LEVEL control to obtain the standard output signal
level.
– Record Mode –
AF OSC
10 k Ω
attenuator
600 Ω
LINE IN
0 dB = 0.775 V
Standard Input Level
input terminal
source impedance
input signal level
Standard Output Level
output terminal
load impedance
output signal level
Test Tape
Type Signal
P-4-A100 10 kHz, –10 dB
P-4-L300 315 Hz, 0 dB
WS-48B 3 kHz, 0 dB
Test Mode
1. Insert a short-circuit plug into TP801 (2P) and turn ON the
power switch. (Earth pin &ª of IC801 and turn ON the power
switch.)
At first, all the fluorescent tubes light up, then the system re-
turns to normal display. (However, "00 00" is not displayed on
the counter.)
2. To release the test mode, remove the short plug and turn off
the power switch.
3. Remove the short plug after completion of adjustment.
SECTION 4

ELECTRICAL ADJUSTMENTS

level meter
47 k Ω
+
set
–
LINE OUT
LINE IN
10 kΩ
0.5 V (–3.8 dB)
LINE OUT
47 kΩ
0.5 V (–3.8 dB)
Used for
Azimuth Adjustment
Playback Level Adjustment
Tape Speed Adjustment
– 10 –
Record/Playback Head Azimuth Adjustment
Procedure:
1. Mode : FWD playback
Test tape
P-4-A100
(10 kHz, –10 dB)
set
2. Turn the adjustment screw for the maximum output levels. If
these levels do not match, turn the adjustment screw until both
of output levels match together within 1 dB.
within
L-CH
1dB
peak
output
level
R-CH
peak
Screw
position L-CH peak
3. Phase Check
Mode : playback
test tape
P-4-A100
(10 kHz, –10 dB)
L-CH
set
R-CH
in phase 45 ° 90 ° 135 ° 180 °
Good
4. After the adjustment, lock the screw with locking compound.
Adjustment Location: Record/Playback head
Adjustment screw
level meter
47 k Ω
+
–
LINE OUT
within
1dB
angle
R-CH peak
oscilloscope
47 k Ω
V H
+
47 k Ω
+
–
–
LINE OUT
Screen pattern
Wrong