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TC-204SD
2-2.
ELECTRICAL
ADJUSTMENTS
AND
MEASUREMENTS
PRECAUTION
1. Clean
the following
parts with an alcohol
moistened swab:
;
* record/playback head
* pinch rollers
* erase head
« rubber belts
* cap stans
* idlers
2. Demagnetize
record/playback
head
with a
head demagnetizer.
3. Do
not
use
magnetized
screwdriver
for
adjustments.
4. After the adjustments, apply a small amount
of a locking compound to the parts adjusted.
5. The adjustments should be performed in the
order arranged in this service manual.
6. The
adjustments
and
the
measurements
should be performed for both L-CH and R-CH
with
rated
power
supply
voltage
unless
otherwise specified.
7. The
record and playback level adjustments
should be carefully performed.
8. Tapes required:
1) blank tapes (completely erased with bulk
eraser)
SONY
CS-10 (HF)
CS-20 (CrO2) with two extra holes
CS-30 (Fe-Cr)
2) test tapes
SONY
P-4-A81S (6.3 kHz, -10 dB)
P-4-A82 (10 kHz, -10 dB)
P-4-L81 (333 Hz, 0 dB)
WS-48 (3 kHz, 0 dB)
9. The switches and the controls should be set
as follows unless otherwise specified.
DOLBY
NR switch:
OFF
LIMITER switch:
OFF
LINE control:
MIN
MIC control:
MIN
TAPE
SELECT switch:
NORMAL
LINE OUT control:
MAX
10. Standard record:
Supply the specified input signal level to the
input jack and set the MIC or LINE control
to obtain the specified output signal level.
Set the LINE
control
to MIN
when
MIC
input is used
or set MIC
control
to MIN
when LINE IN is used.
Normal Input Level
die
3000
10K
input level
Svnde
~104B
(0.77 mV)
(0.25 V)
Normal Output Level
Pine ou]
load impedance
100 kQ
0dB
Tape Speed Adjustment
Procedure:
Mode: Playback
speed checker
SONY
LMF-30
WS-48
(3kHz,
0dB)
LINE
OUT
WS-48
sat
counter
LINE
OUT
Adjust R602 (R607) to obtain specified value.
Specification:
speed checker
digital frequency counter
Frequency
difference
between
beginning and end
of tape should be within | % (30Hz).
Adjustment Location:
R602
(R607)
servo board
R607:
Serial No. 17651 and later (E Model)
Serial No. 15651 and later (AEP Model)
Serial No. 17151 and later (UK Model)
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