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Technical Bulletin T753
Product: A/V Receiver
Hardware Technical Bulletin: T753-H2004-02
Date: June 15
Note:
Previous T.B.’s required:
T
T
DESCRIPTION: At high volume setting with no signal on an un-terminated analogue input,
there maybe some residual noise coming from one or more channels.
REASON: This residual noise is coming from the DSP PC board and power supply ground.
SOLUTION: Perform the following ground changes to lower residual noise.
1. Add jumper wire between DSP AGND (grounding bracket) and Multi-channel RCA (the blue
wire in the photo, use AWG #18). See Figure 1.
Figure 1
Implemented in production from Serial number: R44T75307575
YES T753H2004-01
NO
, 2004 Subject: Residual Noise
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Technical Bulletin T753
Product: A/V Receiver
Hardware Technical Bulletin: T753-H2004-02
2. Add a jumper wire between the multi-channel RCA connector and the Pre Amp connector, must be
18 gauge wire. See figure 2.
Figure 2
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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Technical Bulletin T753
Product: A/V Receiver
Hardware Technical Bulletin: T753-H2004-02
3. For J705B on AUDIO PCB, cut all the AGND pin. That is pin 1, 3, 9 & 12. Please refer
to figure 3.
Figure 3
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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Technical Bulletin T753
Product: A/V Receiver
Hardware Technical Bulletin: T753-H2004-02
4. Float the DSP AGND (including the grounding bracket) from chassis. See figure 4 and 5.
FIGURE 4
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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Technical Bulletin T753
Product: A/V Receiver
Hardware Technical Bulletin: T753-H2004-02
5. Mount the front panel ground cable to the nearest front panel screw. See figure 5.
Figure 5
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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