So I build my pupdac, and all the voltages are correct expect one. The 3.3 v at U4 is a 2.02. Now I am not sure wether the chip is damaged or some capacitor somewhere. I reflowed all the joints from J1 to the checkpoint so I think something is damaged. I just don't know what it is. Can someone pls give the correct voltages of the C13, L1, C4, C7, C5, C1 and the X1 output.
P.S. the chip is recognized by windows, however the right channel does not work, I get clean audio from the left channel though.
O and it seems that my U5 is heating up like crazy, I burned my finger when I touched it, after it was on for a couple of secs.
Your issue is really with U5, I suspect. It may be drawing down the overall voltage of the USB bus. U4 is low, but apparently there's enough there for the computer to recognize it. U4 supplies the voltage for the PCM2707, which controls the USB connection.* Are there any bridges on the U5 chip?
* EDIT: I don't think the PCB would recognize it, otherwise.
Edited by tomb - 2/13/14 at 5:49pm