Aiwa CX-NAK772, Service Manual

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MICRO-
COMPUTER
MICROCOMPUTER
FRONT C.B
FRONT C.B
VSS
VDD
C113
*
%
C113
18
15
Short with tweezers.
Fig-2-2
In such a case, check also if the POWER AMPLIFIER circuit or power supply circuit has any abnormalities or
not.
2-2. Regarding reset
There are cases that the machine does not work correctly because the MICROCOMPUTER is not reset even though the
AC power cord is re-inserted, or the software reset (pressing the STOP key + POWER key) is performed.
When the above described phenomenon occurs, it can leads to wrong judgment as if the MICROCOMPUTER is
defective and to exchange the MICROCOMPUTER. In such a case, perform the forced-reset by the following
procedure and check good or no good of the MICROCOMPUTER.
1
Remove the AC power cord.
2
Short the both ends of the electrolytic capacitor C113 that is connected to VDD of the MICROCOMPUTER with
tweezers.
3
Connect the AC power cord again. If the MICROCOMPUTER returns to the normal operation, the
MICROCOMPUTER is good.
Note: The reference number or MICROCOMPUTER pin number of transistor (Q110) and electrolytic capacitor (C113) can
change depending on the models. Be sure to check the reference numbers on schematic diagram before starting the
discharging work.
2-3.Confirmation of soldering state of MICROCOMPUTER
Check the soldering state of the MICROCOMPUTER in addition to the above described procedures. Be sure to
exchange the MICROCOMPUTER after surely confirming that the trouble is not caused by poor soldering but the
MICROCOMPUTER itself.
Fig-2-1
MICROCOMPUTER
FRONT C.B MAIN C.B
OVER LOAD DET
DC DET
Q110
POWER AMP
POWER AMP
POWER SUPPLY
HOLD
HOLD SW
(
AC DET
PIN101 CON601
1
2
*
1
2
*
In some models, it is PIN
(
.
PIN number is different
depending upon microprocessor.
5
15
18
19 18 18
1
2 1
2
19 .
PIN101
CON601
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