Before Repair And Adjustment; Protection Circuitry; Accessories - Panasonic SC-H M900 Service Manual

SC-HM900
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2
Before Repair and Adjustment
Disconnect AC power, discharge Power Supply Capacitors POWER PCB C556, C557, C558, C559, C561 and TRANS-
FORMER PCB C705 through a 10 Q, 5W resistor to ground.
DO NOT SHORT-CIRCUIT DIRECTLy (with a screwdriver blade, for instance), as this way destroy salid state devices.
After repairs are completed, restore power gradually using a variac, to avoid overcurrent.
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Current consumption at AC 127V, 60Hz in NO SIGNAL mode should be ~800mA.
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.
2.
3.
Turn off the power.
Determine the cause of the problem and correGíit.
Turn on the power once again after one minute.
Note:
Whenthe protection circuitryfunctions,the unitwill notoperateunlessthe poweris first turnedoff andthen on again.
4 Accessories '""
Ac cord 1 pza
(SJA168-1A)
D
tR~~~~~~~)""""""""""""""""""""" 1 pza
~
D
f~s~~~~~-~)""""""""""""""""""""" 1 pza
D Battery (remote control) 2 pzas
(UM-3PA)
e
D
tRMM~~~~~~ support 1 pza
D ~~2~ol~~~~~~113)""""""""""""""""" 1 pza
,..-".
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