Jvc RXR 77 TN Service Manual

Page 1

RX-R77BK

JVC
SERVICE MANUAL

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Contents

Safety Precaution- Power Amplifier Adjustment Procedures ---1-38

139

Instruction Bookw Block Diagram~~-

Description of Major ICs ------------------------------------- 1-26 Remote Control UnithM-SR77U)~ ~~1-41
Internal Block Diagram of Other le- Schematic Diagrams--- Insertion
Internal Wiring of FL Display Printed Circuit Board insertion
Disassembly Procedures --------- Connection Diagramm Insertion
FM/AM Tuner Alignment Procedures ------------------- 1-38 Parts List- --------------------------------------------------- Insertion
No. 20236
Mar. 1991

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1 RX-R77BK

--$afety Precautions

1. The design of this product contains special hardware and many circuits and components
specially for safety purposes. For continued protection, no changes should be made to the
original design unless authorized in writing by the manufacturer. Replacement parts must
be identical to those used in the original circuits. Services should be performed by
qualified personnel only. ,

2. Alterations of the design or circuitry of the product should not be made. Any design
alterations of the product should not be made. Any design alterations or additions will
void the manufacturer's warranty and will further relieve the manufacture of responsibility
for personal injury or property damage resulting therefrom.

3. Many electrical and mechanical parts in the products have special safety-related
characteristics. These characteristics are often not evident from visual inspection nor can
the protection afforded by them necessarily be obtained by using replacement components
rated for higher voltage, wattage, etc. Replacement parts which have these special safety
characteristics are identified in the Parts List of Service Manual. Electrical components
having such features are identified by shading on the schematics and by (A) on the Parts
List in the Service Manual. The use of a substitute repalcement which does not have the
same safety characteristics as the recommended replacement parts shown in the Parts List of
Service Manual may create shock, fire, or other hazards.

4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and
the like to be separated from live parts, high temperature parts, moving parts and/or sharp
edges for the prevention of electric shock and fire hazard. When service is required, the
original lead routing and dress should be observed, and it should be confirmed that they
have been returned to normal, after re-assembling.

5. Leakage currnet check (Electrical shock hazard testing)
After re-assembling the product, always perform an isolation check on the exposed metal
parts of the product (antenna terminals, knobs, metal cabinet, screw heads, headphone jack,
contorl shafts, etc.) to be sure the product is safe to operate without danger of electrical
shock.
Do not use a line isolation transformer during this check.

0 Plug the AC line cord directly into the AC outlet. Using a "Leakage Current Tester,
measure the leakage current from each exposed metal parts of the cabinet, particularily
any exposed metal part having a return path to the chassis, to a known good earth
ground. Any leakage current must not exceed 0.5mA AC (r.m.s.).

0 Alternate check method
Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000
ohms per volt or more sensitivity in the following manner. Connect a 1,5000 10 W
resistor paralleled by a 0.15 pF AC-type capacitor between an exposed metal part and a
known good earth ground.

Measure the AC voltage across the resistor 31231359353
with the AC voltmeter. E ohms/volts, _ _
Move the resistor connection to each exposed O °_ ° "we senstVitYJ
metal part, particularly any exposed metal part
having a return path to the chassis, and 015,; AC Type
meausre the AC voltage across the resistor. -||-
Now, reverse the plug in the AC outlet and math
repeat each measurement. Any voltage W >23}, eggosed
measured must not exceed 0.75VAC (r.m.s.). 15°0910W metal part.
This corresponds to 0.5 mA AC (r.m.s.). Good earth ground

-Warnmg

1. This equipment has been designed and manufactured to meet international safety standards.

2. It is the legal responsibility of the repairer to ensure that these safety standards are
maintained.

3. Repairs must be made in accordance with the relevant safety standards.
4. it is essential that safety critical components are replaced by approved parts.
5. If mains voltage selector is provided, check setting for local voltage.

172(Nn20236)

Page 31

1.

I I LC7218(IC102) : PLL Synthesizer

The main function descriptions
(1) It makes the local oscillation frequency by the control data from 10
(2) Decode the control signal and transmit the signal for receiving conditions.

(3) For the best tuning, count the internal-frequency and transmit the data to IC .

2. Terminal Layout

XINE1V24:IXOUT
cc I: 2 23 :lvSS
DI |: a 22 :l m2
CK r; 4 2i II PD1
_D_0I: 5 20 II VD.)
svcc 6 is :l mosc
TUNED m: 7 18 2| AM-osc
STOPINE s 17 II IFREQ
POWERE 9 16 II FM IF
osci: 10 is :|A_M 1r
MOILQE ii 14 1141
FM 11 13 :I MW

3. Block Diagram

Reference
Driver

Phase Detector

X m 1 Charge Pump

X OUT

Swallow Counter

FMW 1/16, 1/17 4bits

Zbit Programma
AM 5 Divider
c:
DI
CK
no

Universal
Counter

Shift Register & Latch

POWER 05c mono WW L_WIF REQ TUNEDIN STOPIN

4. Pin Function Description

Pin No. Symbol I/O Functions and Operations
1, 24 Xin, Xout llo Crystal oscillator(7.2MHz).
2 CE I Fix the chip enable to H when inputting (DI) and outputting (DC) the serial data.
3 DI I Receive the control data from the controller(lC501).
4 CK I This clock is used to synchronize data when transmitting the data of DI and DO.
5 DO 0 Transmit the data from LC7213 to the controller which is synchronized with CK.
. 6 W .., Not used
7 TUNEDIN I Receive the tuned signal from IC104ILA1266A).
8 STOP IN I Not used
9 POWER --- Not used
10 QSC --- Not used
11 MONO -- It is 'H" on FM-monaural. "L" on FM-stereo.
12 W o It is "L on FM mode.
13 W o It is "L on AM mode.
14 'L-VV -- Not used
15 AM-IF I Universal counter input for AM-IF from IC104(LA1266A).
16 FM-IF I Universal counter input for FM-IF from 1C104(LA1266A).
17 IF REQ O Outputthe IF-signal request to IC104 when the pin-7 (tuned in) goes to "H".
18 AM osc I Input the local oscillator signal of AM.
19 FM osc I Input the local oscillator signal of FM.
20 VDD ~- This is a terminal of power supply.
I 4 PLL charge pump output:\then the local oscillator signal frequency is higher than
21 FBI 0 the reference frequency, high level signals will output. _ .
When it is lower than the reference frequency, low level Signals Will output. When
it is same as reference frequency signals, it will be floating.
22 PD2 0 Not used
23 V55 -~ GND

RX-R77BK

SYC

PDI
PDI

FN-IF

AM-IF

(No,20236)I-3I