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View Full Version : Bad phono input on subwoofer - easy fix?



daws0n
27-10-2014, 21:31
As fate would have it last year I picked up a Kenwood SW500 super woofer from a car boot sale for beer money, which was made for the sub-out of the little class A R-SE7 amplifier I use in the computer room. It's been sat under my desk booming away when the mood takes me without a hitch :)

Recently, it's started making a loud humming noise upon power up (which rises/falls with the volume knob). This stops when the rca cable from the single phono input is unplugged. I've tried various sources, same issue. Was about to chuck it out when I thought I'd have one last fiddle about, turns out that if I apply a little upwards or downwards pressure on the connecting RCA plug the humming stops and music plays again. Loose it go and the humming returns.

Before I go taking this thing apart (there's about 20 allen bolts and umpteen screws to remove split the casing) is it worth trying to fix? The input does feel solid/unbroken but I reckon there's a grounding problem somewhere.. Maybe a bad solder joint on the connection?

synsei
27-10-2014, 22:14
Hi Dawson, I presume you have ruled out the RCA lead as the culprit by substituting it for another? Also, try cleaning the input socket with De-Oxit or a similar product before taking the plunge inside, ya never know ;)

daws0n
27-10-2014, 22:18
Yes mate tried a few cables in case of issue, if only it were that simple! :)

synsei
27-10-2014, 22:23
Yes mate tried a few cables in case of issue, if only it were that simple! :)

Sometimes it is - then it's happy days. Hope it isn't terminal sir ;)

Firebottle
28-10-2014, 06:57
It will almost certainly be a dry joint on the connector. Get that allen key out :eek:

:goodluck: Alan