Posted this on the Link Removed as well, but figured I might as well take advantage of the traffic here on TB
Over the last month the neck pickup in my 4-94 has been dropping out, going completely silent, but not while I'm playing. I've checked the leads, in fact I re-soldered one connection on the blend pot as it looked to be a cold joint and the lead wire at that point seamed weakened but not frayed. I have checked and replaced the battery. I have completely disconnected the neck pickup from the blend pot and ground then tested it with a multimeter and the pickup checked out fine. Lastly, nothing in the control cavity is grounding out.
The odd thing is that I have opened the control cavity on three different occasions over the last month when I noticed that when I turn the blend pot CW that the output from the bass goes gradually silent. I know that this is just the diminishing signal from the bridge pickup that is being cut as I turn the knob.
The first time I opened the cavity and looked around but didn't touch anything. I then plugged the bass back into the amp with the cover off and the neck pickup was working again. I replaced the cover and it still worked. Didn't think too much of it - just "one of those things" so I ignored it
The bass kept working for a few more days, then again I picked up the bass after not playing it for a couple of days and the neck pickup was dead silent again. Once again, I popped the cover to the control cavity, but this time probed around a bit more and this is when I re-soldered the connection that was only mildly suspect as it was the only thing that looked like it could be the culprit - it was the third lug on the bottom tier that goes to the volume pot. Neither of the number 2 lugs on either tier, where the pickup hot leads are connected, seemed damaged or worn in any way. So I tested the bass again after the re-solder and it worked again, voila!
Not so fast... A couple of days ago, it did the same thing. It was fine before I hung it up, but when I went to play it again the other day, once again the neck pickup was silent. This time I pulled the whole LH-3 out and was about to burn it in effigy, but thought better of throwing the baby out with the bath water and replacing the whole amp as I do like what the LH-3/Delano combo brings to the sonic table.
At this point, my biggest suspect is the blend pot, but since there haven't been any other "signs" such as static and the fact that it is still blending in the signal from the bridge pickup I'm not so certain. I'm here to ask for help as I have hit a wall in my knowledge and have my fingers crossed that the LH-3 circuit board isn't the culprit.
Have you tried some contact cleaner in the blend pot? You can disassemble th blend pot and give it a good cleaning. It's meticulous to do but possible. You just have to use a blade or needle nose pliers to bend the tabs on the pot body up. Not many people do it, But it's a handy dissection at times.
You could swap the wiring on the blend to make sure that the pickupisnot issue and that would positively identify the knob or pup as the culprit.
