Harman kardon hk 100 m service manual

Page 2

PRECAUTIONS

1.

Always disconnect the chassis from power line when soldering. Turning the power switch OFF is not enough. Power line
leakage passing throng! the heating element may destroy the transistors.

Never attempt to do any work on the transistor amplifiers without first disconnecting the AC line cord and waiting until
the power supply filter capacitors have discharged.

Replacement for output and driver transistors, if necessary, must be made from the same beta group as the original type.

If one output oansistor burns out (open or short) always remove all the output transistors in that channel and check the bias
adjustment, the control and other parts in the network with an ohmmeter before inserting a new transistor. All transistors
in one channel will be destroyed if the base biasing circuit is open on the emitter end.

When mounting a replacement power transistor, be sure that the bottom of the flange, the mica insulators and the surface of
the heat sink are free of foreign matter,for they may cause transistor failure.

Silicon yease must be applied between the transistor and the mica insulator, and between the mica insulator and the heat
sink for better heat conduction.

Fuses must be replaced with size and type indicated. Use of other types can expose componentsto destructive current levels.

ALIGNMENT PROCEDURES

General Conditions (unless otherwise noted)

9°>'.°S"PS*.N."

Tape Select Switch is LN position.

Dolby NR Switch is OFF position.

Input Selector Switch is LINE position.

MPX Filter Switch is OFF position.

Input Level Controls at maximum.

Output Level Control at maximum.

Bias Fine Trim Control at center.

Connect 10 k ohm (1/4W) carbon resistors across both left and right line output jacks.

VTVM OSCILLDSGOPE

TAPE OUTPUT

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110311 CD
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/ VARIABLE RESISTOR
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I, i M01
1 I DC MOTOR
REC/PLAY
HEAD

HEAD AZIMUTH

ADJUSTMENT SCREW Fig. 1

3 3

HEAD AZIMUTH ADJUSTMENT
Equipment Required: Dual Channel AC V.T.V.M. and 10 kHz Test Tape (TEAC MTT7114l

1.
2.

3.

Connect dual channel AC V.T.V.M. to TP3 (left), TP2 (right) and TP1 (ground).
Play back the "A" side of the test tape and adjust Head Azimuth AdjustmEnt Screw so that the output indicated by the
V.T.V.M. will be maximum and the difference of output between left and right becomes less than 1 dB.
Play back the "B" side of the test tape and adjust Head Azimuth Adjustment Screw for maximum output.
Repeat steps 2 and 3, and adjust Head Azimuth Adjustment Screw until the difference of outputs from side A" and side "B"
becomes less than 1 dB.

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