NAD C-520 Service manual

NAD C520/C521

FRONT PANEL PCB

MODIFICATION

PROBLEM:

You may receive a complaint of the unit producing a very high whistle noise

CAUSE:

The step up transformer for the display circuit is humming

SOLUTION:

1. Insert a transformer with more varnish impregnation

2. Apply glue to fix the step-up transformer to the main pcb

3. Add double sided tape between the cushion at the back of the EL display and the front panel pcb.

Please refer to the drawing below

DOUBLE-SIDED TAPE

CUSHION
EL PLATE

PC SHEETS

LCD

PRODUCTION:

This modification will be implemented in production from serialnumber: G0ZC52107201

PAGE 5-01-01

C521BEE

Technical Bulletin

Date:
Note:

Previous T.B.’s required:

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DESCRIPTION: You may have the complaint that some tracks skip or stops playing
altogether.

REASON: The laser pick up connects to the main pc board via a flat ribbon cable and
possibly is twisted the wrong way . It maybe getting caught on the fuse holders or other
parts. just behind the transport mechanism . See figure 1.

SOLUTION: The ribbon cable needs to be allowed to wrap smoothly as shown in figure 2.

Product: DVD Player
Hardware Technical Bulletin:C521BEE-H2005-04

June 27/05

YES

NO

Subject:

Laser ribbon cable

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

www.nadelectronics.com

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