Deck Electronics (De); Servo System (Aio1) - Philips VR120 Service Manual

8.5

Deck electronics (DE)

Service tasks after replacement of IC 7463:
8.5.1 Motor frequency - adjustment [2492] (OPTION):
Purpose:
To adjust the working frequency of the head motor driver
(not necessary for M63100 BFP).
Result of an incorrect adjustment:
Head motor doesn't start correctly.
Before commencing adjustment:
– bring VCR in to EJECT state
– disconnect set from main power source
– remove cable 8004 from connector 1948
– connect test point DRUM [9417] with 5VS1 [9869] (wires
on component side)
– reconnect to main power source
A: DC, 5V/DIV, 50ms/Div
Connector 1948 PIN1-3
8.6

Servo System (AIO1)

Service tasks after replacement of the head drum SYCA
7004-B or EEPROM.
8.6.1 Setting the gap position (GAP):
Purpose:
To determine the correct head switching point during
playback.
Symptom if incorrectly set:
Head switching fault and/or vertical picture flickers.
– Enter the service test program and, whilst step display is
flashing, enter the step number 51, using the numerical
keys.
– Insert a test cassette (e.g. 4822 397 30103) with the
standard video signal in the VCR.
– By pressing the SELECT key whilst step 51 is flashing,
the automatic adjustment is triggered and stored in the
EEPROM .
0V
1e 2e 1e
2e
153.6 ms = 6e
Electrical alignments
After a correct adjustment, the display shows 1;0 when
incorrect. In case of unsuccessful tuning the VCR ejects the
cassette. To leave the step, press SELECT.
Causes of incorrect adjustment :
Incorrect standard video signal.
Scanner fault.
Microprocessor fault.
8.6.2 "Studio Picture control" adjustment (SPC):
Purpose:
Adjustment of the reference level for the SPC.
Symptom if incorrectly set:
The picture is played back at a lower resolution than would
be possible.
– Video signal via Scart or aerial
– Enter the service test program and, whilst the step is
flashing, input the step number 52, using the numerical
keys.
– Insert SPC Alignment Tape 4822 397 30268.
– By pressing the SELECT key whilst step 52 is flashing,
the recorder makes a recording in SP mode (approx. 10
sec.) and in LP mode (approx. 10 sec.), rewinds and
carries out a playback with automatic adjustment.
– After a correct adjustment the display shows 1, and 0 for
incorrect adjustments. In case of unsuccessful tuning the
VCR ejects the cassette.
To leave the step press SELECT.
VR120 8. GB 93