Nad T 531 B Service Manual 2

Page 2

SECTION 1 . .
SECTION 2 . . .
SECTION 3 . . .
SECTION 4 . .
SECTION 5 . . .

CONTENTS

. .SUMMARY

.CABINET & MAIN CHASSIS
.ELECTRICAL

. .MECHANISM

.REPLACEMENT PARTS LIST

Page 8

DISASSEMBLY

CAUTION BEFORE STARTING SERVICING
Electronic parts are susceptible to static electricity and
proper grounding treatment as required.

may easily and damaged, so do not forget to take a

Many screws are used inside the unit. To prevent missing, dropping, etc. of the screws, always use a
magnetized screw driver in servicing. Several kinds of screws are used and some of them need special
cautions. That is, take care of the tapping screws securing molded parts and fine pitch screws used to secure
metal parts. If they are used improperly, the screw holes will be easily damaged and the parts can not be fixed.

CABINET DISASSEMBLY

1. Top Case
1. Release 7 screws (A). (See Fig. 2-1)
2. Lift the top case with holding the back of it,
and remove it in the direction of the arrow

Top Case

,- w

2.Tray Door
1.Eject the disc tray.
2.Lift up the tray door in the direction of the
arrow.

Tray Door

2-2

3. Front Panel
1. Eject the disc tray. (See Fig. 2-2)
2. Remove the tray door. (See Fig. 2-2)
3. Release 2 screws (B).
4. Pull the front panel toward you while pressing
7 stoppers to disengage, and remove the front
panel. (See Fig. 2-3)

Stopper

Stopper

Front Panel

Page 9

CIRCUIT BOARD DISASSEMBLY

Note: Before removing the main circuit board, be sure to shortcircuit the laserdiode output land.
After replacing the main circuit board, open the land after inserting the flexible connector.
(Refer to Mechanism Disassembly)

1. Disassembling of Main Circuit Board

and Interface Board 2. Digitron and Key Circuit Board
1- Remove the t0P case.(See Fig. 2'1) 1. Remove the front panel.(See Fig. 2-3)
2. Remove 12 SCFeW (C)- 2. Release 4 screws (E), and remove the digitron
3. Remove the deck from Main Circuit Board. circuit board.

4. Remove Main Circuit Board from Interface Board.
5. Remove 2 screw (D).
6. Remove interface Board from the chassis.

Power Code

Fig. 2-5

Page 18

4. Front Circuit (Digitron & key)

Power on.

Is oscillation of

X901 normal? Check Power.

LED ON?

YES YES

Check waveform
of |0901 Pin 6.

Is Digilron on normally? Replace ICQOZ.

YES CD YES

b38032 3";ng No Is waveform of |C901 Check waveform
normally? Pin 40 normal? oi |C901 Pin 22.
YES YES YES Solder Key pan.
NO
Chleégowag/ierfozr; oi _ Replace |0901.
YES

Check waveform

Solder defective parts again. 1 ICQOI Pin 26, 27

Replace IC901.

Check and replace
R903,R912, R904, R905, Replace LED901.
R941, R906, R907.

N0 Does pulse NO

Does remote control
work normally?

Is R0901 Pin 2 5V? Solder deiective pans

appear?

YES YES
ls |0901
Pin 17 connected to Replace RC901.
'C901 Pin 1 7
YES
Complete repairing Front B/D. Replace |0901. Re-solder.
YES +YES 1» Recheck

3-7