hifi engine

Pioneer VSX-D902S humming

Hummin on both channels, not on main amp as goes when the links are removed, require any advice or a manual or both. Thankyou Stuart

Humming on both channels

Humming is usually caused by an open filter capacitor, and usually in or near the power supply. It would be one of the larger say 1/2 inch across & bigger & 100 uf & larger. most can be tested in curcut using a volt meter with capacitance or an older meter with an analog needle set to ohms. For an old meter test: With the unit unplugged...attach the meter leads to the cap leads- the reading should go up & slowly climb- this is the cap charging- now reverse the leads- the needle should drop below zero for a few seconds then start to climb & charge again. This is the cap backfeeding the meter then recharging. If it just goes up a little & stops, the cap will need to be removed & tested out of circut.


Thankyou for your info, as you said, 470Uf @ 16V wouldnt read on ESR in or out of circuit. Thankyou Stuart


Hya, thanks for the info, just so hard to get to PSU section, was wondering if there was a common faults, narrow it down a bit, I have a ESR meter, so best to pull board out and make a start. Its hard to test the unit without almost complete reassemble. Thakyou will get back. Stuart