Harman kardon citation receiver service manual

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The Citation Receiver

Professional Solid State

StereophOnic Receiver

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harman/kardon

£5:

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PRECAUTIONS

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

Never attempt to do any work on the circuits 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 transistor 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 grease 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
components to destructive current levels.

Use a non-conductive, non-ferrous tool when making alignment adjustments. Perform
all specifications tests with all covers and escutcheon in place.