No/low output from P Bass

[Jono Bolton]

I plugged my bass into my amp for the first time in ages today, and noticed that the signal was crackling and cutting out.

After checking the usual suspects (lead, amp head), I worked out that the jack was the culprit; if I moved the lead around the signal would cut in and out. I thought that the jack was possibly touching the cavity and causing it to short, but when I opened it up the jack "arm" has electrical tape on it. I checked the position of the jack in the cavity and screwed the scratchplate back on, but when I plugged my bass into the amp, there was no output. If I listened closely I could hear a vague hint of a signal, and when I turned the amp up, the volume of the signal didn't increase by much, and was soon drowned out by the hum of the amp. 

If I hold the jack in the socket without pushing it all the way in, I can get the full signal, but when I push it in until it clicks, the signal drops again. Any thoughts on what it could be?

[KiOgon]

It seems like the plug going in all the way is making the jack spring contact short onto the cavity wall. Try the bass with the scratch plate lifted up out so the contacts are clear.

 

[Jono Bolton]

3 hours ago, KiOgon said:

It seems like the plug going in all the way is making the jack spring contact short onto the cavity wall. Try the bass with the scratch plate lifted up out so the contacts are clear.

 

Cheers, that was my first thought but it wasn't an issue before. The jack socket is firmly secured, so I don't think it would have turned at any point. I added some additional tape around the jack spring so that any part that potentially could have made contact with the cavity should be protected. I'll try and rotate the jack 180° and see if that works.

[Jono Bolton]

All resolved now. Rotating the socket didn't make a difference, so I'm not quite sure what was causing it to short; possibly one of the lugs on the jack was making a connection with the wall of the cavity. I've lined the tail of the cavity around the jack with electrical tape, including the floor of the cavity, so there is zero chance of it shorting anywhere. I'm not sure what's happened for it to start shorting, it wasn't an issue before. I'm not really sure why the jack on a P Bass is so close to the edge of the cavity; there's minimal clearance in there which could be remedied by the hole for the jack being moved a few mm closer to the tone pot. An email is currently winging it's way to Fender's R&D dept.