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
Service Hint
for C521/C541 ,C520/C540 , C522/C524
If the cd player has a complaint of not able to play a cdr or out of
tolerance discs ,try replacing these capacitors with the following values. This
will also provide a cure on some players for “NO DISC” message.
C520/C521 /C522/C524
C122 is changed to 2.7pF
C123 is changed to 0.01uF
C124 is changed to 22pF
C540/C541
C122 is changed to 2.7pF
C123 is changed to 0.01uF
C124 is changed to 22pF
C311 is changed to 220pF
Production:
This change has been implemented in production from serial number: G19C52113901 - C521/C
Contact:
NAD Electronics International
633 Granite Court
Pickering, ON Canada L1K 3K1
Voice: 905-831-0799 FAX 905-837-6357
www.nadelectronics.com
G19C54108101 – C541/AH
G19C54108401 – C541/C
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