XM-2000R - Sony Car Audio Service Manual (repair manual). Page 3

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This set has protection circuit and indicators. When trouble oc-
curs, LED indicates status.
Each LED lights up in green during normal operation. The color
will change green to flashing red when trouble occurred.

LED

OFFSET (D851)

OVER CURRENT  *1

(D852)

THERMAL (D855)

Problem

•

DC voltages are applied to the
SPEAKER OUT terminal (CN812,
CN813)

•

DC voltages out to the SPEAKER
OUT terminal cause the internal cir-
cuit troubled

•

The SPEAKER OUT terminal is
shorted

•

The internal output element is troubled

•

The temperature rises to unsafe level

Solution

Turn off the power switch. Make sure the speaker cord and
ground lead are securely connect

Turn off the power switch. Make sure the SPEAKER OUT
terminal are not short-circuited

The set heats up abnormally

•

Stereo operation: 1 to 8 

Ω

•

Bridging operation: 2 to 8 

Ω

Make sure to place the set in a ventilated location

(The color will return to green when the temperature returns
to normal)

*1: Does not work in no-signal condition.

To check the system’s status, activate the built in transmitter then
press the 

[TEST TONE]

 button (S801). If the tone is heard, the set

is functioning normally.

When check the protector, do not cancel it.

In case of a failure in this set, the protection circuit functions to
prevent a speaker damage and turn off the power to stop the set
working.
To make the set work at the service, disconnect the JW81 of the
PROTECT board and turn on the power.
Be sure to reconnect the JW81, after the completion of service.

+

+

C867

C871

T851

JW81

PROTECT OFF

(disconnect)

– PROTECT Board –
  (Component Side)