NAD-T753-avr-tb2 维修电路原理图.pdf

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1、Page 1 of 5 Technical Bulletin T753 Product: A/V Receiver Hardware Technical Bulletin: T753-H2004-02Date: June 15, 2004 Subject: Residual Noise Note:Implemented in production from Serial number: R44T75307575 Previous T.B.s required: ? ?YES T753H2004-01 ? ?NODESCRIPTION: At high volume setting with n

2、o 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 AG

3、ND (grounding bracket) and Multi-channel RCA (the blue wire in the photo, use AWG #18). See Figure 1. Figure 1RadioFans.CN 收音机爱 好者资料库Page 2 of 5 Technical Bulletin T753 Product: A/V Receiver Hardware Technical Bulletin: T753-H2004-022. Add a jumper wire between the multi-channel RCA connector and th

4、e Pre Amp connector, must be 18 gauge wire. See figure 2. Figure 2Contact:NAD Electronics International 633 Granite Court Pickering, ON Canada L1K 3K1 Voice: 905-831-0799 FAX 905-837-RadioFans.CN 收音机爱 好者资料库Page 3 of 5 Technical Bulletin T753Product: A/V Receiver Hardware Technical Bulletin: T753-H20

5、04-023. For J705B on AUDIO PCB, cut all the AGND pin. That is pin 1, 3, 9 & 12. Please refer to figure 3.Figure 3Contact:NAD Electronics International 633 Granite Court Pickering, ON Canada L1K 3K1 Voice: 905-831-0799 FAX 905-837-Page 4 of 5 Technical Bulletin T753Product: A/V Receiver Hardware Tech

6、nical Bulletin: T753-H2004-024. Float the DSP AGND (including the grounding bracket) from chassis. See figure 4 and 5. FIGURE 4Contact:NAD Electronics International 633 Granite Court Pickering, ON Canada L1K 3K1 Voice: 905-831-0799 FAX 905-837-Page 5 of 5 Technical Bulletin T753Product: A/V Receiver Hardware Technical Bulletin: T753-H2004-025. Mount the front panel ground cable to the nearest front panel screw. See figure 5.Figure 5Contact: NAD Electronics International 633 Granite Court Pickering, ON Canada L1K 3K1 Voice: 905-831-0799 FAX 905-837-