ESP LTD EC-500 (EMG 81) Grounding Problem

[colynomial]

So I've got this ground hum type problem with my EC-500 and before I go pulling the whole thing appart I'm wondering if anyone can diagnose what exactly I need to do. I've never worked with active pickups before and after opening up the back plate it seems a little bit more complicated than passive.

When I touch the bridge pickup it causes a pretty loud hum to come through my amp. This happens when I'm palm muting where my fingers are hanging over so it kind of comes and goes which makes almost more annoying than if it were constant.

I've found that if I touch the pickup and the volume knob at the same time, the hum goes away. I've actually just got a little piece of insulated wire taped to the pickup and wrapped around the volume knob as a bandaid solution. There is no problem with the neck pickup.

Anyone know exactly what I should be looking for? Everything seems to be in place in underneath the volume/tone knobs from behind so I'm thinking I need to pull the offending pickup right out and check around in there for loose connections or shorts.

 

[DevilJaw]

sounds like the mesh shielding from the white wire from the pickup(the one connected to the volume pot) is making little or no contact. just re-solder it, making sure not to melt through to the inner wire.

 

[colynomial]

Thanks man I'll check it out when I change my strings tomorrow.

 

[kramer1309]

had the same things happen to me when i was installing my 81, it was that the shielding of the white output from the pickup was not grounded..