MICROFILM
SERVICE MANUAL
US Model
Canadian Model
XR-4800
E Model
XR-4790/4800
Model Name Using Similar Mechanism
NEW
Tape Transport Mechanism Type
MG-25F-136
AUDIO POWER SPECIFICATIONS (US model)
POWER OUTPUT AND TOTAL HARMONIC DISTORTION
13 watts per channel minimum continuous average power into 4 ohms, 4
channels driven from 20 Hz to 20 kHz with no more than 1% total
harmonic distortion.
Cassette player section
Tape track
4-track 2-channel stereo
Wow and flutter
0.08% (WRMS)
Frequency response
30 18,000 Hz
Signal-to-noise ratio
58 dB
Tuner section
FM
Tuning range
FM tuning interval:
87.5 107.9 MHz
(XR-4790, XR-4800: US, Canadian model)
50 kHz/200 kHz switchable
87.5 108.0 MHz (at 50 kHz step)
87.5 107.9 MHz (at 200 kHz step)
(XR-4800: E model)
Antenna terminal
External antenna connector
Intermediate frequency
10.7 MHz
Usable sensitivity
8 dBf
Selectivity
75 dB at 400 kHz
Signal-to-noise ratio
65 dB (stereo),
68 dB (mono)
Harmonic distortion at 1 kHz
0.5% (stereo),
0.3% (mono)
Separation
35 dB at 1 kHz
Frequency response
30 15,000 Hz
Capture ratio
2 dB
AM (MW)
Tuning range
AM tuning interval:
530 1,710 kHz
(XR-4790, XR-4800: US, Canadian model)
MW tuning interval:
9 kHz/10 kHz switchable
5311,602 kHz (at 9 kHz step)
530 1,710 kHz (at 10 kHz step)
(XR-4800: E model)
Antenna terminal
External antenna connector
Intermediate frequency
10.71 MHz/450 kHz.
Sensitivity
30 µV
SW (XR-4800: E model)
Tuning range
SW tuning interval:
SW1: 2,940 7,735 kHz
SW2: 9,500 18,135 kHz
(except for 10,140 11,575 kHz)
Antenna terminal
External antenna connector
Intermediate frequency
10.71 MHz/450 kHz
Sensitivity
50 µV
SPECIFICATIONS
XR-4790/4800
Photo: XR-4800
XR-4790, XR-4800: US, Canadian Model
FM/AM CASSETTE CAR STEREO
XR-4800: E Model
FM/MW/SW CASSETTE CAR STEREO
Continued on next page
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TABLE OF CONTENTS
1.
GENERAL
Location of Controls (XR-4790) .................................... 3
Location of Controls (XR-4800) .................................... 4
Resetting the Unit ........................................................... 5
Detaching the Front Panel ............................................... 5
Setting the Clock ............................................................. 5
Installation (US, Canadian model) ................................. 6
Installation (E model) ..................................................... 7
Connection ...................................................................... 8
2.
DISASSEMBLY ......................................................... 10
3.
ASSEMBLY OF MECHANISM DECK ............ 12
4.
MECHANICAL ADJUSTMENTS ....................... 15
5.
ELECTRICAL ADJUSTMENTS
Test Mode ........................................................................ 15
Tape Deck Section .......................................................... 15
Tuner Section .................................................................. 16
6.
DIAGRAMS ................................................................. 19
6-1. Printed Wiring Board MAIN Section ........................ 21
6-2. Schematic Diagram MAIN Section ........................... 23
6-3. Printed Wiring Board PANEL Section (XR-4790) ... 27
6-4. Schematic Diagram PANEL Section (XR-4790) ...... 29
6-5. Printed Wiring Board PANEL Section (XR-4800) .... 31
6-6. Schematic Diagram PANEL Section (XR-4800) ...... 33
6-7. IC Pin Function Description ........................................... 35
7.
EXPLODED VIEWS ................................................ 38
8.
ELECTRICAL PARTS LIST ............................... 42
Flexible Circuit Board Repairing
· Keep the temperature of the soldering iron around 270 °C dur-
ing repairing.
· Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
· Be careful not to apply force on the conductor when soldering
or unsoldering.
Notes on chip component replacement
· Never reuse a disconnected chip component.
· Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
Power amplifier section
Outputs
Speaker outputs
(sure seal connectors)
Speaker impedance
4 8 ohms
Maximum power output 35 W
× 4 (at 4 ohms)
General
Outputs
Power antenna control
lead/Power amplifier
control lead/Telephone
ATT control lead (E model only)
Rear line out (1)
Tone controls
Bass ± 8 dB at 100 Hz
Treble ± 8 dB at 10 kHz
Power requirements
12 V DC car battery
(negative ground)
Dimensions
Approx. 188
× 58 × 181 mm
(7 1/
2 × 2
3/
8 × 7
1/
4 in.)
(w/h/d)
Mounting dimensions
Approx. 182
× 53 × 164 mm
(7 1/
4 × 2
1/
8 × 6
1/
2 in.)
(w/h/d)
Mass
Approx. 1.2 kg (2 lb. 10 oz.)
Supplied accessories
Parts for installation and connections (1 set)
Front panel case (1)
Design and specifications are subject to change without notice.
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SECTION 1
GENERAL
This section is extracted from
instruction manual.
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