Jvc XVM 50 BK Service Manual

Page 2

XV-MSOBK

-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 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 observed, and it should be confirmed that they have been returned
to normal, after reassembling.

5. Leakage current check (Electrical shock hazard testing)
After reassembling 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.

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, 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 1,5009 10W resistor paralleled by
a 0.15uF AC-type capacitor between an exposed

AC VOLTMETER
metal part and a known good earth ground. (Having 1000
Measure the AC voltage across the resistor with the d ohms/volts,
AC voltmeter. or more sensitivity)
Move the resistor connection to each exposed ° °
metal part, particularly any exposed metal part 0.15UF ACTYPE
having a return path to the chassis, and measure .
the AC voltage across the resistor. Now, reverse -"- 333:1?
the plug in the AC outlet and repeat each W): V : each exposed
measurement. voltage measured Any must not 15009 10W metal part.

exceed 0.75V AC (r.m.s.).This corresponds to 0.5
Good earth ground

- Warning

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.

A CAUTION Burrs 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 31

MN67705EA (2/3)

HnNQ Synbol l/O Function
47 [REF3 - Connects with unused DVSS
48 VCOF2 i Connects with unused DVSS
49 DVSS - Ground for digital circuit
50 VCOES - Connects with unused DVSS
51 DVSS * Ground for digital cirucuit
52 DVDD - Power supply for digital cirucuit
53 SUBC 0 CD sub-code (ODC)
54 BLKCLK 0 CD sub-code synchronous signal (ODC)/Jump output of one at DVD
55 MONC 0 Monitor terminal C
56 NCLDCK O Sub-code data frame clock (ODC)
57 LRCK 0 LR channnel data strove CIRC(ODC)
58 NTRON O L: Tracking ON (ODC)
59 DVSS 7 Ground for digital cirucuit
60 DATO O CIRC / Binary making DVD data output
61 DAT1 O CIRC / Binary making DVD data output
62 DAT2 O CIRC / Binary making DVD data output
63 DAT3 O ClRC / Binary making DVD data output
64 CHCK4 O Synchronous clock of DATO~ 3
65 DVSS 7 Ground for digital circuit
66 DACCLK O
67 DACLRCK l Connects with unused DVSS
68 DACDATA l Connects with unused DVSS
69 ClRClRQ 0 RAM with built-in CIRC exceeds/ Underflow interrupt
70 IPFLAG O CIRC error flag
71 MOND 0 Monitor terminal D
72 TX 0 Digital audio interface
73 DVSS * Ground for digital cirucuit
74 DVDD 7 Power supply for digital cirucuit
75 AVSS 7 Ground for analog cirucuit
76 VREFLAD 7 AD subordinate position standard voltage (0.6:O.1v)
77 VREFMAD - It is a place standard voltage in AD (1.4i0.1V)
78 VFtEFHAD i High-ranking AD standard voltage (2.2 : 0.1V)
79 AVDD - Power supply for analog circuit
80 VREFC(AD12) l
81 JITOUT(AD11) l Jitter signal(FEP)
82 LDCUR(AD10) | Laser drive current signal
83 VREFOP - Operation amplifier standard voltage(VREFC)
84 RFENV(AD9) I FtFENV(FEP)
85 N.C.(ADB) | Connects with VREFC
86 N.C.(AD7) l Connects with VREFC
87 TG(ADG) l Tangential Phase difference (FEP)
88 VREFHDA - High-ranking AD standard voltage (2.2 : 0.1V)
89 VREFMDA - It is a place standard voltage in AD (1.4:0.1V)
90 VREFLDA 7 AD subordinate position standard voltage (O.6:0.1v)
91 TE(AD5) l Tracking error (FEP)
92 TROFS(AD4) l Tracking drive IC input offset
93 FE(AD3) l Focus error (FEP)

XV-M50BK

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