Sony RMT-V259M, Service Manual

Page: 89 / 117

6-3
2-3. SYSTEM CONTROL SYSTEM CHECK
2-3-1. Clock Oscillation Level Check (MA-388 board)
[Adjustment Purpose]
To adjust the precision of the clock. If this specification is not
satisfied, the clock will lose or will gain time.
Mode E-E
Signal Arbitrary
Measurement Point IC160 Pin
rs
Measuring Instrument Voltmeter
Specified Value 4.5V ± 0.5Vp-p
[Adjusting method]
1)
Connect JL141 with a voltmeter.
2) Check that the clock oscillation level satisfies the specified
value.
2-4. SERVO SYSTEM CHECK
2-4-1. RF Switching Position Check (MA-388 board)
[Adjustment Purpose]
To adjust the link of the A-ch and B-ch of the tape playback outputs.
To make the unit compatible with other tapes and units. If this
specification is not satisfied, the link will appear on the screen and
the screen will be disrupted, etc.
Mode Playback
Signal Alignment tape: SP mode color bar
portion
[Adjustment method]
1)
Connect MA-388 board CN262 pin 5 (AV ADJ) short to GND
more than 300 msec.
2) Check that “AP” indicator on the display window turns on.
3) Press EJECT button. (RF switching position adjustment is
performed automatically. )
4) Perform “Hi-Fi Switching Position Adjustment”.
2-4-2. Hi-Fi Switching Position Check
(MA-388 board)
[Adjustment Purpose]
To adjust the link of the A-ch and B-ch of the tape playback outputs.
To make the unit compatible with other tapes and units. If this
specification is not satisfied, the switching noise will be heard, etc.
Mode Playback
Signal Alignment tape: SP mode color bar
portion
Measurement Point CH1: MA-388 board CN301 pin 1
(HF ADJ)
CH2: MA-388 board CN262 pin
2
(RF SWP)
Measuring Instrument Oscilloscope
Specified Value A = minimum
Note: Perform “RF Switching Position Adjustment” before this adjustment.
[Adjustment method]
1)
Connect MA-388 board CN262 pin
5
(AV ADJ) and GND
with a jumper wire.
2) Check that “AP” indicator on the display window turns on.
3) Remove the jumper wire.
4) Press REC button.
5) Check that “AH” indicator on the display window turns on.
6) Press and PROGRAM– buttons and minimize
the part A of PB AF RF signal.
7) Press PAUSE button.
8) Check that the “AH” indicator turns off.
Fig. 6-2-3.
A
2 V
CH1
CH2