Audio Pre-Amp And Audio Phasing Tests; Main Audio Filter; Figure 91. General Location Of The Audio 750 Hz Lpf - NORCAL NC2030 Manual

Audio Pre-amp and Audio Phasing Tests

Apply 9v.
Check the input 3.3v to the board to make sure it is ok.
Check the 5-8v input to the board to make sure it is ~7v.
Check that TP2 and TP3 have ~1.5v across them.
Check all four corner pins of U5 - TLV2464. They should all be at ~ 1.5v
Disconnect the 9v battery.

Main Audio filter

Figure 91. General location of the Audio 750 Hz LPF

Norcal NC2030 v5 12-18-05
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