NAD 522/L40
MODIFICATION
Adding Protection circuit after changing the laser mechanism
This will prevent further damage by ESD, power surges etc.
MODIFICATION:
After changing the laser mechanism (partno: 4102-5002-0) please perform the following modification:
1) Change R137 from 10 Ohm to 20 Ohm 1/8 W min.
2) Add a diode 1N4148 between LD and GND on J2 (cable connection to laser unit), Kathode to LD.
3) Cut trace just after collector Q101.
4) Add coil 10uH in between here.
The required parts are available from FED in a small kit, partno: 522-LASER-PROT-KIT
PRODUCTION:
Please note this modification is being implemented in running production.
The Nad 524 already has this modification except for: 1) Change R137
PAGE 5-99-01
NAD 522/L40
MODIFICATION
Adding Protection circuit after changing the laser mechanism
This will prevent further damage by ESD, power surges etc.
MODIFICATION:
After changing the laser mechanism (partno: 4102-5002-0) please perform the following modification:
1) Change R137 from 10 Ohm to 20 Ohm 1/8 W min.
2) Add a diode 1N4148 between LD and GND on J2 (cable connection to laser unit), Kathode to LD.
3) Cut trace just after collector Q101.
4) Add coil 10uH in between here.
The required parts are available from FED in a small kit, partno: 522-LASER-PROT-KIT
PRODUCTION:
Please note this modification is being implemented in running production.
The Nad 524 already has this modification except for: 1) Change R137
PAGE 5-99-01
Service Tip L40
Signal display circuit change
PROBLEM: Poor sensitivity of the signal strength bar graph.
CAUSE: The polarity of capacitor( C739 10uF/16Vor 25V)and the pcb
marking is reversed on the board.
SOLUTION: Invert cpacitor( C739 10 uF/16V or 25V) by connecting its
negative lead to ground and the positive lead to pin 12 of U701.
PRODUCTION:
This modification has been implemented in production from serial number:G13L4013553
Contact:
NAD Electronics International
633 Granite Court
Pickering, ON Canada L1K 3K1
Voice: 905-831-0799 FAX 905-837-6357
NAD@www.NADelectronics.com
PAGE 1-01-01
Service Hint L40
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.
C122 is changed to 2.7 pF.
C123 is changed to 0.01 uF.
C124 is changed to 22 pF.
PRODUCTION:
This change has been implemented in production from serial number:G1XL4014653-14752
Contact:
NAD Electronics International
633 Granite Court
Pickering, ON Canada L1K 3K1
Voice: 905-831-0799 FAX 905-837-6357
www.nadelectronics.com
Service Hint L40
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.
C122 is changed to 2.7 pF.
C123 is changed to 0.01 uF.
C124 is changed to 22 pF.
PRODUCTION:
This change has been implemented in production from serial number:G1XL4014653-14752
Contact:
NAD Electronics International
633 Granite Court
Pickering, ON Canada L1K 3K1
Voice: 905-831-0799 FAX 905-837-6357
www.nadelectronics.com
Service Tip L40
Signal display circuit change
PROBLEM: Poor sensitivity of the signal strength bar graph.
CAUSE: The polarity of capacitor( C739 10uF/16Vor 25V)and the pcb
marking is reversed on the board.
SOLUTION: Invert cpacitor( C739 10 uF/16V or 25V) by connecting its
negative lead to ground and the positive lead to pin 12 of U701.
PRODUCTION:
This modification has been implemented in production from serial number:G13L4013553
Contact:
NAD Electronics International
633 Granite Court
Pickering, ON Canada L1K 3K1
Voice: 905-831-0799 FAX 905-837-6357
NAD@www.NADelectronics.com
Service Information L40
Circuit Change
PROBLEM: Original transformer for the L40 back light display was
changed in production.
The first transformer was a 3 pin module inverter package. The
second transformer is a 9 pin stand alone transformer. The part numbers for
the two parts is shown below.
Order part according to the diagram below.
9 PIN TRANSFORMER 3 PIN TRANSFORMER MODULE
PART NUMBER#1806-2320-0 PART NUMBER#1806-2217-0
(new version) (original in service manual)
Contact:
NAD Electronics International
633 Granite Court
Pickering, ON Canada L1K 3K1
Voice: 905-831-0799 FAX 905-837-6357
www.nadelectronics.com
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