jonnythenotes Posted December 6, 2016 Share Posted December 6, 2016 I recently bought a 1974 P bass and a problem seems to randomly keep manifesting itself. Without reason, the volume tone seems to reverse its function, whereby turning it clockwise turns the volume down, instead of increasing it, and the tone control seems to lose all the bottom end when turned as if trying increase it. This is accompanied by humming and crackling when touching either of the two knobs. When you jiggle the guitar jack plug, it can fix the problem, and also, if you squeeze down on the scratchplate either side of the jack socket, this will also correct it. It has been in to my local guitar tech chap a couple of times, and he tells me that the pots are ok, and perhaps it is time to change the jack socket over. Before I do this, I thought I would check with you guys, as I really don't want to change anything on it if poss, as being a 74 model, original fixtures a fittings are what help retain its value. I have been told that the foil which covers the horn part of the inner scratchplate below the controls is a part of shielding/earthing/grounding, and also there is a crack in the scratchplate which starts at the Jack socket, and spreads to the last screw of the scratch plate... Would this have an adverse effect? It just seems odd that pressing down on the scratchplate at this point corrects the problem temporarily. Having said that, I got it back from the guitar chap today, and so far, it hasn't happened again, but I can't keep my fingers crossed at every gig that it won't occur again. Would sooner fix it once and for all, without putting any new parts in unless absolutely vital. Sorry for my vague description, but I am afraid it's the best I can do. Thanks.. Quote Link to comment Share on other sites More sharing options...
Grangur Posted December 6, 2016 Share Posted December 6, 2016 (edited) Sounds like you need someone to trace through the whole circuit and re-solder all the connections. Something is loose or poorly connected. I'd be happy to take a look, but where are you? Edited December 6, 2016 by Grangur Quote Link to comment Share on other sites More sharing options...
gary mac Posted December 6, 2016 Share Posted December 6, 2016 I had the same on one of my vintage P basses, almost identical to the symptoms you have described. I replaced the output socket, figuring that even if it were to affect resale value, I would rather have a playable instrument. I also eventually replaced the volume pot. Switch cleaner would help for a while but the problem would return. I kept the original parts and passed them on when I sold the bass. I sold the bass, for the price I wanted, so never regretted carry out those essential repairs. Quote Link to comment Share on other sites More sharing options...
Grangur Posted December 6, 2016 Share Posted December 6, 2016 [quote name='gary mac' timestamp='1481059855' post='3189443'] I had the same on one of my vintage P basses, almost identical to the symptoms you have described. I replaced the output socket, figuring that even if it were to affect resale value, I would rather have a playable instrument. I also eventually replaced the volume pot. Switch cleaner would help for a while but the problem would return. I kept the original parts and passed them on when I sold the bass. I sold the bass, for the price I wanted, so never regretted carry out those essential repairs. [/quote] Its a simple fact of life that electric instruments will never live to any kind of old age with the original components. They don't have the longevity of a classical instrument. I've even got a friend, as classical guitarist, who says a classical guitar has a useful life of only 10 years. Quote Link to comment Share on other sites More sharing options...
KiOgon Posted December 6, 2016 Share Posted December 6, 2016 (edited) You mention the foil on the underside of the scratch plate & the fact that the plate is cracked. If your jack socket doen't have a wire on both tags and was relying on mechanical contact for ground via the foil - that's your problem! You need to solder a wire from the central 'hole' tag of the socket to a pot body, assuming the pots are already wired together. I suppose you could get away with just repairing the foil, making sure there is electrical continuity between all the electrical bits - pots and socket. Can you put up a picture of the innards + wiring? Cheerz, John Edited December 6, 2016 by KiOgon Quote Link to comment Share on other sites More sharing options...
jonnythenotes Posted December 6, 2016 Author Share Posted December 6, 2016 Guys.... I can't thank you enough for that advice. I will get it looked at... Grangur...I am in Lichfield, Staffs.... Will keep you posted, and thanks again to all of you... Quote Link to comment Share on other sites More sharing options...
jonnythenotes Posted December 6, 2016 Author Share Posted December 6, 2016 Ps... Kiogon, I will get a few pics on over the next day or so if it happens again. It seems to be ok now..but I am not 'gig it' confident Quote Link to comment Share on other sites More sharing options...
KiOgon Posted December 7, 2016 Share Posted December 7, 2016 [quote name='jonnythenotes' timestamp='1481068392' post='3189542'] Ps... Kiogon, I will get a few pics on over the next day or so if it happens again. It seems to be ok now..but I am not 'gig it' confident [/quote]If it is as I suspect - it's certainly not fit to gig - not reliable at all I'm sure you can lift the pick guard and have a peek - but - If you need to get it looked at, please don't take it back to this guy ."It has been in to my local guitar tech chap a couple of times, and he tells me that the pots are ok", find someone local to you from here maybe; http://basschat.co.uk/topic/277468-bcers-prepared-to-help-fix-a-bass/page__fromsearch__1 Cheerz, John Quote Link to comment Share on other sites More sharing options...
wateroftyne Posted December 7, 2016 Share Posted December 7, 2016 Forget about the original fittings - get it fixed. Or... stand it in the corner and let it gather dust. Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted December 7, 2016 Share Posted December 7, 2016 Hi jonnythenotes As Grangur says, it needs the continuity checking. Basically something is randomly disconnecting or shorting, maybe within one of the pots but more likely one of the external wires or connections. It's a straightforward job. I'm just north of Derby and very happy to take a look for nowt. Fixing this kind of stuff, providing it is done properly, is expected and will not reduce the value - certainly not as much as the alternative of selling something as a 'non-runner'. PM me and we can arrange you coming to me or me coming to Lichfield. Andy Quote Link to comment Share on other sites More sharing options...
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