System Control System Check; Clock Oscillation Level Check (Ma-388 Board); Servo System Check; Rf Switching Position Check (Ma-388 Board) - Sony SLV-SE850 Service Manual

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
Signal
[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
Signal
Measurement Point
Measuring Instrument
Specified Value
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 PROGRAM+ 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.
A
CH1
CH2
6-3
Playback
Alignment tape: SP mode color bar
portion
Playback
Alignment tape: SP mode color bar
portion
CH1: MA-388 board CN301 pin 1
(HF ADJ)
CH2: MA-388 board CN262 pin 2
(RF SWP)
Oscilloscope
A = minimum
2 V
Fig. 6-2-3.