Sony XR-4800, Service Manual

Page: 13 / 37

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SECTION 4
MECHANICAL ADJUSTMENTS
SECTION 5
ELECTRICAL ADJUSTMENTS
1. Clean the following parts with a denatured-alcohol-moistened
swab:
playback head pinch roller
rubber belt capstan
idlers
2. Demagnetize the playback head with a head demagnetizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the power supply
voltage unless otherwise noted.
•
Torque Measurement
Mode Torqu Meter Meter Reading
Forward CQ-403A
more than 90 g
(more than 3.18 oz)
Reverse CQ-403R
more than 90 g
(more than 3.18 oz)
•
Tape Tension Measurement
Mode Torqu Meter Meter Reading
Forward CQ-102C
30 - 65 g•cm
(0.42 - 0.90 oz•inch)
Forward
CQ-102C
0.5 - 4.5g•cm
Back Tension (0.01 - 0.06 oz•inch)
Reverse CQ-102RC
30 - 65 g•cm
(0.42 - 0.90 oz•inch)
Reverse
CA-102RC
0.5 - 4.5g•cm
Back Tension (0.01 - 0.06 oz•inch)
FF, REW CQ-201B
60 - 200 g•cm
(0.83 - 2.78 oz•inch)
TEST MODE
This set have the test mode function. In the test mode, FM Auto
Scan/Stop Level and AM (MW) Auto Scan/Stop Level adjustments
can be performed easier than it in ordinary procedure.
<Set the Test Mode>
1. Set the “power select” switch (S801) is “A” position.
2. Turn ON the regulated power supply. (All LEDs on the set
lights up, and the clock is displayed.)
Note:
Press the
[OFF]
button, if the clock is not displayed.
3. Push the preset
[4]
button.
4. Push the preset
[5]
button.
5. Press the preset
[1]
button for more than two seconds.
6. Then the display indicates all lights, the test mode is set.
<Release the Test mode>
1. Push the
[OFF]
button.
2. Return the “power select” switch (S801) to initially set posi-
tion.
See the adjustment location from on page 16 for the
adjustment.
0 dB= 0.775 V TAPE DECK SECTION
Tape Speed Adjustment
Setting:
Speed checker Frequency counter
–1.5 to +2.5% 2,955 to 3,075Hz
Procedure:
1. Put the set into the FWD PB mode.
2. Adjust adjustment resistor for inside capastan motor so that
the reading on the speed checker or frequency counter becomes
in specification.
Specification: Constant speed
+ –
test tape
WS-48A
(3 kHz, 0 dB)
speed checker
or
frequency counter
10 k
Ω
set
LINE OUT
Adjustment Location: See page 16.