Jvc UXF 70 MD Service Manual

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UX-F70MD/UX-F72M D

-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 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, 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 areturn 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 1,5009 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 ' 7 ohms/volts,
AC voltmeter. or more sensitivity)
Move the resistor connection to eachexposed metal ° °
part, particularly any exposed metal part having a Q15): AC TYPE
return path to the ch'ass1s, and meausre the AC _"_ Placethis
voltage across the reSIstor. Now, reverse the plug In probe on
the AC outlet and repeat each measurement. voltage 'W\, ' > each exposed
measured Any must not exceed 0.75 V AC (r.m.s.). 15009 10W metal part.

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

-Warnlng
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.lf 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,

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pay attention to such burrs in the case of preforming repair of this system.

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UX-F70MD/UX-F72MD

lRemoving the cartridge holder assembly
(See Fig.14 and 15)

1. Remove the two screws l on the upper side of the Slide bar
loading assembly.

V Cartridge holder assembly

Eject bar

I Removing the slide bar and the eject bar
(See Fig.14 and 15)

- Prior to performing the following procedure, remove
the cartridge holder assembly.

1. Remove the slide bar upward. snde bar

2. Move the eject bar outward until it stops as shown in
Fig.14. Push the convex part 9 on the bottom of the
body and remove the eject bar from the chassis.

Eject bar

UD base

Cartridge holder assembly

Fig.15

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UX-F70MD/UX-F72M D

l Reinstalling the Pickup Assembly Part k
(Refer to Figs. 15 and 16.)

Reference: Refer to the explanation of " Removing
the Pickup" on the preceding page.

Pickup

1. Fit the P.S. spring and rack plate to the pickup. assembly

2. Insert the shaft into the pickup.

9°

Engage the hook k of the pickup assembly with the
CH. base assembly first, and set the part] of the
rack plate in the opening | next. Then, reinstall the
pickup assembly while shifting it to the T-T side
(inward) so that the part m of the rack plate is
positioned as shown in Fig. 16.

CH. base
assembly

4;

. Move the pickup assembly to the center position
and fasten the shaft with the two screws D. (Make
sure that the part n of the rack plate is correctly
engaged with the middle gear.)

U1

. After passing the flexible wire coming from the
pickup through the opening of the CH. base
assembly, connect it to the connector CN601.

Note: When reinstalling the pickup assembly,
remove the solder from the shorting round
after connecting the flexible wire coming from
the pick to the connector CN601.

Part n
Rack plate

I Removing the Feed Motor Assembly

(Refer to Fig. 17.) FE?

' Remove the CL. base assembly and tray.
- Remove the mechanism P.C. board.

Remove the two screws E fastening the feed motor
assembly from the top of the mechanism assembly.

Feed motor assembly

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UX-F70MD/UX-F72M D

3. Pin function (2/3)

Pin No. Symbol |/o Function

44 XCAS 0 External DRAM CAS output.

45 A09 0 External DRAM address output.

46 XRAS 0 External DRAM RAS output.

47 XWE 0 External DRAM write enable.

48 D1 l/O External DRAM data bus.

49 D0 l/O External DRAM data bus.

50 DZ l/O External DRAM data bus.

51 D3 l/O External DRAM data bus.

52 MDDTI l MD-DATA mode 1 switching input. (Low : normal mode ; high : MD-DATA mode 1)

53 ASYO O Playback EFM full-swing input. (Low : vss ; high : Vdd)

54 ASYl l Playback EFM comparator slice voltage input.

55 AVDD - Analog power supply.

56 BIAS l Playback EFM comparator bias current input.

57 RH | Playback EFM RE signal input.

58 AVSS - Analog ground.

59 PCO 0 Phase comparison output for master PLL of playback digital PLL and recording
EFM PLL.

60 FiLI | Filter input for master PLL of playback digital PLL and recording EFM PLL.

61 FILO 0 Filter output for master PLL of playback digital PLL and recording EFM PLL.

62 CLTV | Internal VCO control voltage input for master PLL of playback digital EFM PLL and
recording EFM PLL.

63 PEAK | Peak hold signal input for quantity of light.

64 BOTM | Bottom hold signal input for quantity of light.

65 ABCD | Signal input for quantity of light.

66 FE | Focus error signal input.

67 AUXl | Auxiliary input 1.

68 VC | Center voltage input.

69 ADIO | Monitor output for A/ D converter input signal.

70 AVDD - Analog power supply.

71 ADRT l Voltage input for the upper limit of the A/ D converter operating range.

72 ADRB l Voltage input for the lower limit of the A/ D converter operating range.

73 AVSS - Analog ground.

74 SE | Sled error signal input.

75 TE | Tracking error signal input.

76 DCHG | Connect to he low-inpedance power supply.

77 APC | Error signal input for laser digital AFC.

78 ADFG l ADIP binary FM signal (22.05 i 1kHz) input.

79 FOCNT O CXA2523 current source setting output.

80 XLRF O CXA2523 control latch output. Latched at the falling edge.

81 CKRF O CXA2523 control shift clock output.

82 DTRF O CXA2523 control data output.

83 APCREF 0 Reference PWM output for laser AFC.

84 LDDR O PWM output for laser digital AFC.

85 TRDR 0 Tracking servo drive PWM output. (,)

86 TFDR 0 Tracking servo drive PWM output. (+)

87 DVDD - Digital power supply.

88 FFDR 0 Focus servo drive PWM output. (+)

89 FRDR 0 Focus servo drive PWM output. (7)

90 F84 O 4Fs output. (176.4kHz)

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UX-F70MD/UX-F72MD

Pin No. Symbol |/O Function
21 VREF 0 Reference voltage output.
22 EQADJ l/O Equalizer center frequency setting pin.
23 3TADJ l/O BPFST center frequency setting pin.
24 Vcc - Power supply.
25 WBLADJ I/O BPF22 center frequency setting pin.
26 TE 0 Tracking error signal output.
27 CSLED - Connects the sled error signal LPF capacitor.
28 SE 0 Sled error signal output.
29 ADFM O ADIP FM signal output.
30 ADIN I ADIP signal comparator input.
31 ADAGC - Connects the ADIPAGC capacitor.
32 ADFG O ADIP2 binary value signal output.
33 AUX O 13 output / temperature signal output. Switched with serial commands.
34 FE 0 Focus error signal output.
35 ABCD 0 Reflection light quantity signal output for the main beam servo detector.
36 BOTM O RF/ABCD bottom hold signal output.
37 PEAK 0 Peak hold signal output for the RF/ABCD signals.
38 RF 0 RF equalizer output.
39 RFAGC - Connects the RFAGC capacitor.
40 AGCI l RFAGC input.
41 COMPO 0 User comparator output,
42 COMPP | User comparator non-inverted input.
43 ADDC l/O Connects the capacitor for ADlP amplifier feedback circuit.
44 OPO 0 User operational amplifier output.
45 OPN l User operational amplifier inverted input.
46 RFO 0 RF amplifier output. Eye pattern checkpoint.
47 MORFl l input of the groove RF signal with AC coupling.
48 MORFO O Groove RF signal output.

I GP1UM271XK (l0901) : Receiver for remote

FD+tA+1>F

Limiter

Integrator Comparator

B.P.F Demodulalor

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