How do check my computer for a grounding issue?
I seem to get a lot of interference through my home theatre pc in respect to video ground loop and speaker hum. Using a voltage meter, can check somehow if my problem is a ‘grounding‘ problem?
The most common cause of ground loop hum in home theater is a bad ground from the cable TV or satellite connection. If you disconnect this and the hum goes away, work on that side of things.
With a meter set on a low AC volts range, this will show up if you disconnect the cable from the cable box or whatever, then measure AC volts between the cable shield and pretty much any ground point on the HT.
Beware, though, that such readings can be misleading with some components. Your meter is likely a very high impedance type (all digital multimeters are). It is very common for HT components with two-prong plugs to have a very tiny bit of leakage onto the chassis. This can read as high as 60 volts (half the AC line voltage) referenced to true AC neutral but there’s no current behind it; it isn’t necessarily a problem. But it CAN be…