AIWA NSXMT721
Manual de Servicio

NOTE 1. Forced
When across

ON

BEFORE

STARTING
ofelectrol~ic

REPAIR
capacitor ofpower
uses though relay circuit

discharge
repair is going

supply

block
supply block, Ifrepair electric isattempted potential is kept charged the

to be attempted capacitors

in the set that 102) even

in the power cord

theelectrolytic defect to prevent

(CIOl,

ACpower

is removed.

inthiscondition,

secondary In order

can occur. the secondary trouble, perform the following measures before starting repair work.

Discharae

�o

DrOC@dUre
the AC power a discharging at bothends. chassis. end (+VH) of the discharging of Cl 01. (For resistor two to the cord. resistor Connect at an end of lead theother endofthe wire that lead

I

II

o @

Remove Connect hasclips wire

II

MAIN C.B

to metal

(3 @

Contact positive Contact

the other (+) side the same

seconds) as step

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

resistor

@) to the negative way. (For that two

in the same

seconds) across C101 and C102 has decreased & L 6

@

Check

voltage using-a

1 V or less

multimeter

or an oscilloscope.

Select
Charging

a discharging
voltage

resistor
(V)

referring
Discharging

to the following

table.

Fig-1

Rated (Clol,
25-48 49-140

power

(W)

Parts

number

102)

resistor 100 220

(Q) 3 5 87-AOO-247-090 87-AOO-232-090

Note:

The

reference

numbers

(C101,

C102)

of the electrolytic on schematic

capacitors diagram

can change before

depending

on the models. work.

Be sure

to check

the

reference

numbers

of the charging

capacitors

starting

the discharging

2. Check
Be sure confirming

items
to check that

before

exchanging
items before

the MICROCOMPUTER
exchanging is surely the MICROCOMPUTER. Exchange the MICROCOMPUTER after

the following

the MICROCOMPUTER

defective.

2-1.

Regarding
When correctly. the HOLD When

the

HOLD
terminal

terminal
(INPUT) is �L�,

of the

MICROCOMPUTER
is �H�, be turned the MICROCOMPUTER on. Therefore, be sure is judged to check to be operating voltage of

the HOLD When terminal

of the MICROCOMPUTER the main power cannot

this terminal before

the terminal

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

the MICROCOMPUTER that triggers

abnormalities

detection

on the MAIN

C. B. that

sets the HOLD

terminal

*

Good

or no good

judgement
power. power

of the

MICROCOMPUTER

Turn

on the AC main that the main

Confirm not, When

is turned

on and the HOLD

terminal

of the MICROCOMPUTER

keeps

the �H

level

or

the HOLD

terminal

is �L� level,

the abnormality

detection

circuit

is judged

to be working

correctly

and the

MICROCOMPUTER

is judged

to be good.
d �.� .� -�. �.� -�

�.�

.�.
FRONT C.B

;

I

MAIN C.B ,
In

1:
I
PIN1OI

I
CON601

some

models,

it is PIN

@.

MICROCOMPUTER

&� @ POWER AMP

POWER

AMP

POWER r PIN �.� number is different upon microprocessor. -�. �-�. �.� .�. �.� depending

SUPPLY

..

Fig-2-1

-4-