Sony TC-204SD - Electrical Adjustments and Measurements; Tape Speed Adjustment; Standard Record Procedure

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
(3kHz,
OdB)}
digital
frequency
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)