In another thread I'm working on a TV digital-to-analog converter. This thread is more generally about the power supply to such a device. I think mine has a problem.
The onboard switching supply is the high voltage area on the right. The big cap is rated to 400V and has ~170V on it. The white jumper far right is the AC 120V input from the wall.
Here's my question about those 5 components in the middle of the back edge. All but the inductor have 5.0V DC across them, including the diode, and 10.0V AC. I also see 10V AC on those empty pads to the right of the diode. All voltages measured with my cheap HF meter.
Those readings don't make sense to me. Isn't 5V DC across a diode a bad sign? And 10V AC on the electrolytics?
The onboard switching supply is the high voltage area on the right. The big cap is rated to 400V and has ~170V on it. The white jumper far right is the AC 120V input from the wall.
Here's my question about those 5 components in the middle of the back edge. All but the inductor have 5.0V DC across them, including the diode, and 10.0V AC. I also see 10V AC on those empty pads to the right of the diode. All voltages measured with my cheap HF meter.
Those readings don't make sense to me. Isn't 5V DC across a diode a bad sign? And 10V AC on the electrolytics?