Jvc LE 50 B Service Manual

Page 1

L-E50 B

JVB

SERVICE MANUAL

'ILlINEAR TR fiCKlNG FULLY AUTOMtlfTIC TURNTABLE,

MODEL L-E5OB

Contents

Page Page

Safety Precautions .............................................. 1- l 9. Rope Suspension .......................................... 1-10

1. Features ..................................................... 1- 2 10. Block Diagram ............................. _ ................ 111

2. Specifications .............................................. 1- 2 11. Check of Power Supply P.C. Board ................... 1-11

3. Controls and Functions .................................. 1- 3 12. Adjustment Procedures ................................. 1 -12

4. Service Precautions ...................................... 1- 5 12-111 Offset Adjustment ...... . ....................... 1-12
5. TechnicalExplanation .................................... 1- 5 12-(2) Track Interval (Marker Space) Detection

5-H) Programmed Playback .......................... 1- 5 Sensor Sensitivity Adjustment .............. 1 -12

512) Explanation of Microprocessor Pins ......... 1- 6 12-(3) Lead-In Adjustment ............................. 1-12

6. Stylus Replacement ...................................... 1- 8 1244) Motor Speed Adjustment ..................... 1-12

6-) Removal ............................................ 1- 8 12-(5) Program Position (Touch-Down

6-i2) Attachment ........................................ 1~ 8 Position) Adjustment ........................... 1-12

7. Cartridge Replacement .................................. 1- 8 13. Connection Diagram ...................................... 1- 1 3

8. RemovalProcedures .................................... .. 1- 9 14. Power Cord Connections in Different Areas ....... 1-14

8-(11 Disassembly Procedures ....................... 1- 9 15 Troubleshooting ........................................... 1-15

842) Removal and Attachment of Platter 16. L- E508 Schematic Diagram ........................... 1-18

Compartment Door .............................. 1-10 Parts List .............................. Separate- volume insertion

No. 27 1 9

This manual combines two single volumes: Service manual and Parts list.

Mar. 1984

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Safety Precautions

l. The design of this product contains special hardware. Do not use a line isolation transformer during this check.
many circuits and componets specially for safety pur- 0 Plug the AC line cord directly into the AC outlet.
poses. Using a Leakage Current Tester", measure the
For continued protection, no changes should be made to leakage current from each exposed metal part of the
the original design unless authorized in writing by the cabinet, particularly any exposed metal part having a
manufacturer. Replacement parts must be identical to return path to the chassis, to a known good earth
those used in the original circuits. Service should be per- ground. Any leakage current must not exceed
formed by qualified personnel only. 0.5 mA AC (r.m.s.).

2. Alterations of the design or circuitry of the product 0 Alternate check method
should not be made. Any design alterations or additions Plug the AC line cord directly into the AC outlet. Use
will void the manufacturer's warranty and will further an AC voltmeter having 1,000 ohms per volt or more
relieve the manufacturer of responsibility for personal in- senSItivity in the following manner. Connect a
jury or property damage resulting therefrom. 1500 Q 10 W resistor paralleled by a 0.15 pF AC-

3. Many electrical and mechanical parts in the product type capacitor between an exposed metal part and a
have special safety-related characteristics. These known good earth ground,
characteristics are often not evident from visual inspec- Measure the AC voltage across the resistor with the
tion nor can the protection afforded by them necessarily AC voltmeter.
be obtained by using replacement components rated for Move the resistor connection to each exposed metal
higher voltage, wattage, etc. Replacement parts which part, particularly any exposed metal part having a
have these special safety characteristics are identified in return path to the chassis, and measure the AC
the parts list of Service manual. Electrical components voltage across the resistor. Now, reverse the plug in
having such features are identified by shading on the the AC outlet and repeat each measurement. Any
schematics and by ( A ) on the parts list in Service voltage measured must not exceed 0.75 V AC
manual. The use of a substitute replacement which does (r.m.s.). This corresponds to 0.5 mA AC Ir.m.s.).

not have the same safety characteristics as the recom-
mended replacement part shown in the parts list in Ser-
vice manual may create shock, fire, or other hazards.
4. The leads in the products are routed and dressed with
ties, clamps, tubings, barriers and/or the like to be
separated from live parts, high temperature parts, mov-

ing parts and/or sharp edges for the prevention of elec-
tric shock and fire hazard. - AC VOLTMETER
When service is required, the original lead routing and CD (HAVING 1000 ON,
dress should be observed, and they should be confirmed , o 0 OR MORE SENSITIVITY)
to be returned to normal, after re-assembling.
5. Leakage current check Q1 5 #F AC_TYPE
(Safety for electrical shock hazard) -l
After re-assembling the product, always perform an
isolation check on the exposed metal parts of the l>
Products (antenna terminals, knobs, metal cabinet, 1500 9 10 W EINAEECTfiEXEggEE
screw heads, headphonejack, control shafts, etc.) to be
sure the product is safe to operate without danger of GOOD EARTH GROUND METAL PART

electrical shock.

CHECKING YOUR LINE VOLTAGE (For U.S. Military Market and Other Countries)

Before inserting the power plug, please check this setting to see that it corresponds with the line voltage in
your area. If it doesn't, he sure to adjust the voltage selector switch to the proper setting before operating this
equipment. The voltage selector switch is located bottom board.

CAUTION Before selecting the Voltage selector swtich" to proper voltage disconnect the power plug.

1-1 (No. 2719)