I asked the question below.

I found out that there is a mistake on the PCB. The right channel negative output is missing the trace that connects the two pads. I am using the outer one that is connected to the circuit the inner pad is not connected to the outer. So of course I was not able to measure anything using it. The pads are connected properly on the other outputs. I am not sure if this is documented anywhere.


I just finished building a Legato III. I was able to easily zero out the left channel outputs measuring between the - and + outputs. I can not get the right channel to zero out. The value starts at 100mv and drifts all over the place. Turning the trim pot does bring it down some, but the it drifts back up. I am not using output caps. I will pull the test rig apart and see if I can find the usual suspects, cold solder joints etc. Is there something in particular I should be looking for?

Thanks

Edited by user Sunday, February 12, 2012 9:33:38 AM(UTC)  | Reason: Not specified