Testing the Headphone and Mixer

Generally, this section is best tested when all the jumpers are attached.

Headphone Testing

Here is a list of voltages that should be seen on the LA4140. The best way to test it is to set the x0xb0x to random mode and the volume full up. Make sure you do not have headphones connected.

Pin DC Offset AC Volts
1 1v 40mv
2 3v 400mv
3 3v 400mv
4 3v 2v
5 0v 0v
6 3v 2v
7 6v 0v
8 6v 2v
9 3v 0v

These values are approximate, variations of 10% should be expected.