Sony PMC-DR45L Service Manual ▷ View online
– 17 –
Tape Speed Adjustment
Procedure:
Mode: playback
Mode: playback
32
Ω
test tape
WS-48B
(3 kHz, 0 dB)
WS-48B
(3 kHz, 0 dB)
set
i
(headphones) jack (J301)
digital frequency
counter
counter
Mode
Tension Meter
Meter Reading
FWD
CQ-403A
more than 100 g
REV
CQ-403R
(more than 3.52 oz)
Mode
Torque Meter
Meter Reading
FWD
CQ-102C
36 – 61 g•cm
(0.50 – 0.89 oz•inch)
FWD
2.0 – 6.0 g•cm
Back tension
(0.028 – 0.076 oz•inch)
REV
CQ-102RC
36 – 61 g•cm
(0.50 – 0.89 oz•inch)
REV
2.0 – 6.0 g•cm
Back tension
(0.028 – 0.076 oz•inch)
61 – 143 g•cm
FF, REW
CQ-201B
(0.89 – 2.00 oz•inch)
Adjust so that the frequency at the beginning and that at the end of
tape winding are between 2,970 and 3,030 Hz.
tape winding are between 2,970 and 3,030 Hz.
Adjustment Location:
SECTION 5
ELECTRICAL ADJUSTMENTS
SECTION 4
MECHANICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab:
record/playback/erase head
pinch roller
rubber belts
capstan
idlers
2. Demagnetize the record/playback/erase head with a head de-
magnetizer. (Do not bring the head demagnetizer close to the
erase head portion.)
erase head portion.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power sup-
ply voltage unless otherwise noted.
Torque Measurement
Tape Tension Measurement
Standard Output Level
Test Tape
5-1. TAPE SECTION 0 dB = 0.775 V
1. The adjustments should be performed in the order given in the
service manual. (As a general rule. Playback circuit adjustment
should be completed before performing recording circuit ad-
justment.)
should be completed before performing recording circuit ad-
justment.)
2. The adjustments should be performed for both L-ch and R-ch
unless otherwise indicated.
SP OUT
PHONES
Load impedance
4
Ω
32
Ω
Output level
0.775 V (0 dB)
0.25 V (–10 dB)
Type
Signal
Used for
WS-48B
3 kHz, 0 dB
Tape speed adjustment
P-4-A100
10 kHz, –10 dB
Head azimuth adjustment
Digital frequency counter
2,970 to 3,030 Hz
Adjust so that the value on the frequency counter is 3,000 Hz.
Specification Values:
TC board
M691
TAPE SPEED
Adjustment
Adjustment
– 18 –
screw
position
position
L-CH
peak
peak
within
1dB
1dB
output
level
level
L-CH
peak
peak
R-CH
peak
peak
within
1dB
1dB
screw
angle
angle
R-CH
peak
peak
3. Phase Check
Mode: FWD/REV playback
4. After the adjustment, lock the screws with locking compound.
Record/Playback/Erase Head Azimuth Adjustment
Procedure:
1. Mode: FWD/REV playback
1. Mode: FWD/REV playback
2. Turn the adjustment screw for the maximum output levels. If
these levels do not match, turn the adjustment screw until both
of output levels match together within 1 dB.
of output levels match together within 1 dB.
Adjustment Location:
+
–
–
set
32
Ω
level meter
test tape
P-4-A100
(10 kHz, –10 dB)
P-4-A100
(10 kHz, –10 dB)
i
(headphones) jack (J301)
+
–
–
V
H
+
–
Screen pattern
set
L-CH
32
Ω
test tape
P-4-A100
(10 kHz, –10 dB)
P-4-A100
(10 kHz, –10 dB)
i
(headphones) jack (J301)
R-CH
32
Ω
oscilloscope
Good
Wrong
in phase 45
°
90
°
135
°
180
°
screwdriver
FWD
(forward)
(forward)
REV
(reverse)
(reverse)
– 19 –
FM FREQUENCY COVERAGE
CHECK
Frequency Display
87.5 MHz
108 MHz
Reading on Digital voltmeter
1.4 ± 0.2 V
6.9 ± 0.2 V
Adjustment Part
<confirmation> <confirmation>
FM TRACKING CHECK
Adjust for a maximum reading on level meter.
<confirmation>
<confirmation>
87.5 MHz
108 MHz
MW FREQUENCY COVERAGE
ADJUSTMENT
Frequency Display
531 kHz
1,611 kHz
Reading on Digital voltmeter
0.9 ± 0.1 V
4.9 ± 0.5 V
Adjustment Part
L5
<confirmation>
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T1
450 kHz
MW TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L3
CT1
621 kHz
1,404 kHz
LW FREQUENCY COVERAGE
ADJUSTMENT
Frequency Display
153 kHz
279 kHz
Reading on Digital voltmeter
0.7 ± 0.2 V
5.2 ± 0.1 V
Adjustment Part
<confirmation>
CT3
LW TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L4
CT2
162 kHz
261 kHz
Adjustment Location: TUNER board (See page 20.)
5-2. TUNER SECTION 0 dB = 1 µV
Precautions in Repairing
Note : As a tuner unit (TU1) is difficult to repair if faulty,
replace it with new one.
• FM Section
Setting:
BAND button: FM
BAND button: FM
22.5 kHz frequency
deviation by 400 Hz signal
output level : as low as possible
deviation by 400 Hz signal
output level : as low as possible
• MW/LW Section
Setting:
BAND button: MW or LW
BAND button: MW or LW
30% amplitude
modulation by 400 Hz signal
output level : as low as possible
modulation by 400 Hz signal
output level : as low as possible
• Connecting Level Meter (FM, MW and LW)
• Connecting Digital Voltmeter (FM, MW and LW)
• Repeat the procedures in each adjustment several times, and the
frequency coverage and tracking adjustments should be finally
done by the trimmer capacitors.
done by the trimmer capacitors.
FM terminal
(J1)
(J1)
FM RF signal
generator
generator
0.01
µ
F
set
Put the lead-wire
antenna close to
the MW/LW loop
antenna.
antenna close to
the MW/LW loop
antenna.
AM RF signal
generator
generator
i
(headphones) jack (J301)
set
32
Ω
level meter
(range: 0.5-5 V ac)
(range: 0.5-5 V ac)
digital
voltmeter
voltmeter
tuner board
TP (VT)
TP (VT)
– 20 –
Adjustment Location:
L5
MW
FREQUENCY
COVERAGE
ADJUSTMENT
MW
TRACKING
ADJUSTMENT
CT3
LW
FREQUENCY
COVERAGE
ADJUSTMENT
LW
TRACKING
ADJUSTMENT
T1
AM
IF
ADJUSTMENT
CT2
L4
L3
CT1
TP(VT)
J1
FM
TERMINAL
– TUNER BOARD (COMPONENT SIDE) –
Click on the first or last page to see other PMC-DR45L service manuals if exist.