Hi! Help with troubleshooting the usb receiver on the esoteric d-02 DAC. The problem is that it is not detected by the computer. The drivers don't help. Windows writes that an unknown device. Everything works on another DAC of the same type. I called the whole board, all of it. I checked all the voltages and found different voltages at two points, otherwise everything is absolutely the same in voltage. I attach a photo of the board. In the photo, I marked in pink near the chip where there are voltage discrepancies. Also yellow and pink are marked relative to each other, the voltage with the working board is also different. I also checked nec 2801c-4 by moving it from one board to another, it works, the problem is not in it.
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You need a schematic. If you can't find one then you can try to sketch up a diagram of the part of the circuit you want to troubleshoot. Also download datasheets for all ICs in that part of the circuit. Other than that you can visually inspect the circuitry with a magnifying glass to look for cracked capacitors, burnt spots on ICs, cracked solder joints, bulging electrolytics, etc. If none of that works you might need to send the dac to Esoteric or an authorized service center.