Page 1
Service Information T761
Circuit Change
PROBLEM: Distortion ,hum and or crackling noises from all speakers in
any surround mode. Stereo mode not affected.
CAUSE: Capacitor C107 2200uF 16V not filtering the ripple to the 5v
regulators on the DSP board due to prolonged heating of C107.
SOLUTION: Replace C107 rated 85 degrees celcius should be changed to
2200 uf 16v 105 degrees celcius rating.
Note: The units affected for the T761 are serial numbers starting with
#GOYT761 and GOZT761. Later production have the higher rated capacitor
implemented.
T751 and some T760 units may be affected.
It is advisable to change the 85 degree capacitor on T751, T761, and
T760 units being serviced for any reason.
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 2
Service Tip T761
Circuit Change
PROBLEM: The power amp gets very hot during continuous operation.
CAUSE: Heatsink temperature runs very hot before fan turns on.
SOLUTION: Change R5120 from 4k7 to 2k to increase sensitivity of the
thermal sensor for the fan to turn on at 85 C.
Also change jumper wire J758 to 1N4001 diode on the main board to
improve heat dissipation on Q565.
PRODUCTION:
This circuit change has been implemented in production from serial number:G13T76102701
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 3
Service Tip T761
Modification
PROBLEM:Whistle noise at the –61dB volume setting when Dolby Digital
signal from DVD player connected to digital input.
CAUSE: Noise coming from U605.
SOLUTION:To improve compensation from U605 .
Remove C662 and C663. Add 200-220 pF ceramic capacitor between pins 2
and 3 of U605. Add 200-220pF capacitor between pins 5 and 6 of U605.
PRODUCTION:
This modification has been implemented in production from serial number: G13T76102701.
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
Page 4
NAD T761
MODIFICATION
PROBLEM:
Sometimes when turning the unit on or off there will be a pop on the subwoofer pre-out
CAUSE:
The muting of the subwoofer preamp comes in too late
SOLUTION:
The following changes, unless otherwise specified, need to be preformed on the multi channel PCB.
Please refer to attached diagram.
1. Remove R665
2. Add a wire between C681 positive pole & D734 cathode side ( D734 is located on the main board)
3. Add a 22uF / 10V ce Capacitor over R6111, the negative pole needs to face up.
PRODUCTION:
This modification is implemented in production from Serial no. G0YT76100901
PAGE 7-01-01
Page 5
Service Information T761
Circuit Change
PROBLEM: The power amp gets very hot during continuous operation.
CAUSE: Heat sink temperature runs very hot before fan turns on.
SOLUTION: Change R5120 from 4k7 to 2k to increase sensitivity of the
thermal sensor for the fan to turn on at 85 C.
Also change jumper wire J758 to 1N4001 diode on the main board to
improve heat dissipation on Q565. J758 is located near R733/R734 390 1/2W
resistors. The cathode (white band) should be to the left or heat sink side when
looking at the front of the receiver.
PRODUCTION:
This circuit change has been implemented in production from serial number:G13T76102701
Contact:
NAD Electronics International
633 Granite Court
Pickering, ON Canada L1K 3K1
Voice: 905-831-0799 FAX 905-837-6357
NAD@www.NADelectronics.com
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