Disconnect AC power, discharge Power Supply Capacitors C5820 and C5840 through a 10
Ω
, 5W resistor to ground.
DO NOT SHORT-CIRCUIT DIRECTLY (with a screwdriver blade, for instance), as this may destroy solid state devices.
After repairs are completed, restore power gradually using a variac, to avoid overcurrent.
Current consumption at AC 120V, 60 Hz in NO SIGNAL mode (volume min at CD mode) should be ~600mA.
2 Before Repair and Adjustment
3 Protection Circuitry
The protection circuitry may have operated if either of the following conditions are noticed:
·
No sound is heard when the power is turned on.
·
Sound stops during a performance.
The function of this circuitry is to prevent circuitry damage if, for example, the positive and negative speaker connection
wires are
“shorted”, or if speaker systems with an impedance less than the indicated rated impedance of the amplifier are used.
If this occurs, follow the procedure outlines below:
1.Turn off the power.
2.Determine the cause of the problem and correct it.
3.Turn on the power once again after one minute.
Note :
When the protection circuitry functions, the unit will not operate unless the power is first turned off and then on again.
4 Prevention of Electro Static Discharge (ESD) to Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged easily by electricity. Such components commonly are called
Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field-effect
transistorsand semiconductor “chip” components. The following techniques should be used to help reduce the incidence
of component damage caused by electro static discharge (ESD).
1. Immediately before handling any semiconductor component or semiconductor-equiped assembly, drain off
any ESD on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available
discharging ESD wrist strap, whichshould be removed for potential shock reasons prior to applying power to the unit under
test.
2. After removing an electrical assembly equiped with ES devices, place the assembly on a conductive surface
such as aluminium foil, to prevent electrostatic charge build up or exposure of the assembly.
3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.
4. Use only an anti-static solder remover device. Some solder removal devices not classified as “anti-static (ESD
protected)” can generate electrical charge to damage ES devices.
5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ES devices.
6. Do not remove a replacement ES device from its protective package until immediately before you are ready
to install it. (Most replacement ES devices are packaged with leads electrically shorted together by conductive foam,
aluminium foil orcomparable conductive material).
7. Immediately before removing the protective material from the leads of a replacement ES device, touch the
protective material to the chassis or circuit assembly into which the device will be installed.
Caution
Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.
8. Minimize body motions when handling unpackaged replacement ES devices. (Otherwise harmless motion
such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static
electricity (ESD) sufficient todamage an ES device).
IMPORTANT SAFETY NOTICE
There are special components used in this equipment which are important for safety.
These parts are marked by in the schematic diagrams, Exploded Views and replacement parts list. It is essential that these
critical parts should be replaced with manufacturer´s specified parts to prevent shock, fire, or other hazards. Do not modify the
original design without permission of manufacturer.
4
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Summary of Contents for SC-TM23
Page 8: ...9 Operation Procedures 8 ...
Page 44: ...44 15 Block Diagram ...
Page 45: ...45 ...
Page 46: ...46 ...
Page 47: ...47 6601 6601 565 ...
Page 48: ...48 ...
Page 49: ...49 565 9 ...
Page 50: ...50 ...
Page 51: ...51 16 Voltage Measurement ...
Page 52: ...52 ...
Page 54: ...17 1 A CD Servo Circuit 54 ...
Page 55: ...55 ...
Page 56: ...56 17 2 B Main Tuner Circuit ...
Page 57: ...57 17 3 B Main Circuit ...
Page 58: ...58 ...
Page 59: ...59 ...
Page 60: ...60 ...
Page 61: ...17 4 C Panel Circuit 61 ...
Page 62: ...62 ...
Page 64: ...64 17 6 H Power Circuit ...
Page 65: ...65 17 7 I Deck Circuit J Mechanism Circuit ...
Page 66: ...66 ...
Page 68: ...68 18 2 B Main P C B ...
Page 69: ...69 ...
Page 70: ...70 18 3 C Panel P C B ...
Page 71: ...71 ...
Page 72: ...72 18 4 D Transformer P C B ...
Page 73: ...73 18 5 E CD Detect P C B F Spindle Position P C B G CD Loading P C B K Tuner Pack P C B ...
Page 74: ...18 6 H Power P C B 74 ...
Page 75: ...75 ...
Page 76: ...18 7 I Deck P C B J Deck Mechanism P C B 76 ...
Page 77: ...77 19 Wiring Connection Diagram ...
Page 78: ...78 20 Illustration of IC s Transistors and Diodes ...
Page 82: ...82 22 Troubleshooting Guide ...
Page 86: ...86 23 1 2 Deck Mechanism Parts List ...
Page 89: ...89 23 2 2 CD Loading Mechanism Parts List ...
Page 123: ...2 Connection of the Speaker Wiring 3 Cabinet Parts Location 123 ...