Nad L-75 Service Information

NAD L75

CN83

MODIFICATION

PROBLEM:

When the headphones are plugged in the subwoofer is not muting.

CAUSE:

Mute line on subwoofer does not activate when the headphones are plugged in.

SOLUTION:

The headphones, On line(h/p on) from the control (front panel) board can be connected via a wire and a

4.7k ohm resistor to the base of Q302 on the surround pc board. See diagram 1 ,2 and 3. Glue resistor to
surround pc board after to prevent wire and resistor from moving.

Diagram 1

L75 FRONT PANEL PC BOARD (PARTIAL REAR VIEW) L75 SURROUND PC BOARD

PIN
12

GROUND
PLANE
PINS 13&14

ADD WIRE AS
SHOWN

(PARTIAL REAR VIEW)

ADD
RESISTOR

4.7K OHM
TO BASE OF

Q302

PAGE 7-01-03

Service Information L75

Circuit Change

PROBLEM: Transformer buzzes.

CAUSE: Transformer’s core is causing hum and is transferred to the chassis.

SOLUTION: Replace transformer with new low hum type. Install rubber
padding on under side of transformer.

PRODUCTION:

This change has been implemented in production from serial number:A14L7502001

Contact:

NAD Electronics International
633 Granite Court
Pickering, ON Canada L1K 3K1
Voice: 905-831-0799 FAX [phone]
[e-mail]