Jvc RX 558 RBK Service Manual

Page 2

RX-

558VBK/RX-558RBK

--Safety Precautions

1.This 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 manufacturers
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 replacement 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 obsen/ed, 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. control
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.

.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 , particularly 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.)

.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 1,500910W resistor paralleled by
a 0.15uF AC-type capacitor between an exposed

metal part and a known good earth ground. E fixgénhgoEgEF-t
Measure the AC voltage across the resistor with the ohms/volts,

AC voltmeter. or more sensitivity)
Move the resistor connection to eachexposed metal

part, particularly any exposed metal part having a (115),: AC TYPE

return path to the chassis, and meausre the AC .
voltage across the resistor. Now, reverse the plug in -'"- 32:: :25
the AC outlet and repeat each measurement. voltage Wt > each exposed
measured Any must not exceed 0.75 V AC (r.m.s.). 150052 10W metal part.

This corresponds to 0.5 mA AC (r.m.s.).
Good earth ground

- Warning

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

2.lt 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.

A CAUTION Buns formed during molding may be left over on some parts of the chassis. Therefore,
pay attention to such burrs in the case of preforming repair of this system.

Page 27

2.Pin Function (1/2)

RX-558VBK/RX-558RBK

Pin No. Symbol I/O Function

1 ECKO - Non connect
2 ECKI I Amplifier input terminal for external clock input.
3 A.GND - Ground terminal.(For crystal oscillator circuit)
4 A.GND - Ground terminal.(For DAC L channel)
5 LchOUT O DAC analog signal output terminal.(L- channel)
6 V-REF1 - Reference voltage terminal.(For DAC L channel)
7 A.5V - Power supply terminal.(For DAC L channel)
8 A.5V - Power supply terminal.(For DAC Fl channel)
9 V~REF2 - Reference voltage terminal.(For DAC R channel)
10 RchOUT O DAC analog signal output terminal.(R channel)
11 A.GND - Ground terminal.(For DAC R channel)
12 A.GND - Ground terminal.(For DAC C channel)
13 NC 0 DAC analog signal output terminal.(c channel)
14 CchOUT O DAC analog signal output terminal with attenuator.(For C channel)
15 V-REF3 - Reference voltage terminal.(For DAC 0 channel)
16 A.5V - Power supply terminal.(For DAC C channel)
17 VFtO 0 Reference voltage terminal for attenuator.(0utput buffer)
18 VRI l Reference voltage terminal for attenuator.(lnput buffer)
19 A.5V - Power supply terminal.(For DAC 3 channel)
20 V-REF4 - Reference voltage terminal.(For DAC 8 channel)
21 schOUT O DAC analog signal output terminal with attenuator.(For S channel)
22 NC - Non connect.
23 A.GND - Ground terminal.(For DAC 8 channel)
24 D.GND - Ground terminal.

25~29 NC - Non connect.
30 D.5V - Power supply terminal.
31 D.5V - Power supply terminal.(For DLRAM)
32 D.GND - Ground terminal.(For DLRAM)

33~43 NC - Non connect.
44 D.GND - Ground terminal.

45.46 NC - Non connect.
47 D.5V - Power supply terminal.

48~53 NC . Non connect.
54 - Ground terminal.
55 - Power supply.
56 - Ground terminal.
57 RESET | Power supply.

Page 31

RX-558VBK/RX-558RBK

(5)AUDIO P.C.BOARD Removal (Fig.6)

1.Ftemove the rear panel.

2.Remove the VIDEO P.C.Board and TUNER P.C.Board.

3.Disconnect the connector CN512 on the AUDIO
P.C.Board.

4.Disconnect to the card wire CN314 on the AUDIO
P.C.Board.

5.Disconnect the connector CN712 on the AMP P.C.Board.

6.Pu|lout the connector P.C.Board.

7.Remove 4 screws "G" on the AUDIO P.C.Board.

8.Remove the AUDIO P.C.Board.

- G Connector P.C.Board
F'g6 (Standing substrate)

(6)MAIN P.C.BOARD Removal (Fig.6,7,8)

Poe. H AUDIO

1.Ftemove the rear panel. P.C.Board

2.Pu|l out the AMP P.C.Board and connector P.C.Board.
3.Remove 8 screws H" on the MAIN P.C.Board.
4.Remove 8 screws "I" on the Power transistor.
5.Disconnect the connector CN511 and wire
CN831 on the MAIN P.C.Board.
6.Each tie band is cut out. AMP PW»
7.Remove 2 screws "J" on push switch of the front side. (SWIWB)
8.Remove nut on terminal of the headphone.
9.The solder of the wire connected with the
transformer is removed.
10.Remove the MAIN P.C.Board.

Guam Fig.7

(7)Front P.C.BOARD Removal (Fig.9)

1.Ftemove the top cover.

2.Ftemove the Front panel assembly.

3.Ftemove the master volume knob and nut.
4.Ftemove the 13 screws "K" on the Front P.C.Board.

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