AIWA NSXMA845
Service Manual

NOTE 1. Forced
When

ON

BEFORE

STARTING ofelectrol~ic

REPAIR capacitor ofpower
relay circuit cordis

discharge
is going

supply

block
supply Ifrepair block, electric potential is kept charged seconda~ across defect

repair

to be attempted (CIOl,

in the set that though

uses

in the power removed.

theelectrolytic can occur. In order

capacitors

102)even

ACpower

isattempted

inthiscondition,

to prevent

the secondary

trouble,

perform

the following

measures

before

starting

repair

work

Discharge

procedure

I II
Remove Connect has clips wire the AC power a discharging at both ends. cord. resistor Connect at an end the other of lead end wire that of the lead to metal the chassis. other end (+VH) of the discharging (For two resistor seconds) as step @ same way. to the

MAIN

C.B

Contact positive Contact

(+) side the same

of C101.

end of the discharging (-) side (-VH) of C102

resistor in the

to the negative (For Check
to

two

seconds) voltage using across C101 and C102 has decreased (
I

that

1 V or less

a multimeter

or an oscilloscope.

@

@

Select
Charging

a discharging
voltage

resistor
(V)

referring
Discharging

to the following

table.

Fig-1

Rated

power

(W)

Parts

number

(Clol,
25-48

102)

resistor

(Q)

100 220 numbers (C101, C102) of the

3 5 electrolytic on schematic capacitors diagram

87-AOO-247-090 87-AOO-232-090 can before change starting depending on the models. work. Be sure to check the

49-140
Note:

The

reference

reference

numbers

of the charging

capacitors

the discharging

2.

Check

items

before
the following

exchanging
items before

the

MICROCOMPUTER
the MICROCOMPUTER. Exchange the MICROCOMPUTER after confirming

Be sure to check that

exchanging

the MICROCOMPUTER

is surely

defective.

2-1.

Regarding
When When terminal When

the

HOLD
terminal is �L�,

terminal
(INPUT) the main

of the

MICROCOMPUTER
is �H�, on. the MICROCOMPUTER be sure to check is judged the terminal to be operating voltage correctly.

the HOLD this terminal

of the MICROCOMPUTER power cannot be turned

Therefore,

of the HOLD

before

exchange. is not the abnormality defective, detection the HOLD circuit terminal can also go �L� when the POWER terminal AMPLIFIER to �L�. has any

the MICROCOMPUTER that triggers

abnormalities

on the MAIN

C. B. that

sets the HOLD

q

Good @
@ @

or no good

judgement
power. power

of the

MICROCOMPUTER

Turn

on the AC main that the main the

Confirm When

is turned is �L�

on and the HOLD the abnormality

terminal

of the MICROCOMPUTER circuit is judged to be

keeps working

the �H�

level

or not. and the

HOLD

terminal

level,

detection

correctly

MICROCOMPUTER

is judged

to be good.
.�. �.� c.B .�. �.�

�.�.�.
FRONT C.B � IYAIN

i
MICROCOMPUTER PIN101 @� ~ �, CON601

In some

models,

it is PIN

@.

OVER ~

LOAD

DET

.

.

I
PIN �.�

dnumber is different upon microprocessor. .�. �-

I

I
PI
QIIO I ~~

AC DET

POWER

SUPP �LY I

depending

]

.�..

Fig-2-l

�5�