Greggo Posted October 11, 2015 Share Posted October 11, 2015 (edited) Please can someone give me an idea what this issue is and whether aa full rewire is needed or just one pot. Ive taken back my old Yamaha RBX5 in trade but unfortunately it has come back to me with an electrical issue. It is P/J but it seems only the P pickup is functioning but the blend just seems to behave like a volume pot and in the supposed bridge position it's just a lower level p pickup sound. Any ideas on what might be the issue? Am I best rewiring? Edited October 11, 2015 by Greggo Quote Link to comment Share on other sites More sharing options...
JapanAxe Posted October 11, 2015 Share Posted October 11, 2015 Most likely either the connection from the J pickup has come adrift, or the pickup itself has failed. Quote Link to comment Share on other sites More sharing options...
Greggo Posted October 17, 2015 Author Share Posted October 17, 2015 I took out the wiring and I think it looks like it has had a bodge wiring since its been out-of my hands! The wiring doesn't seem to match the conventional for vol - blend - tone. On the blend pot itself true middle lugs are soldered to each other and the inputs are on the outside? Doesn't seem right all all so going to get the soldering iron out when I get chance. I am debating changing blend to a 3 way switch instead. Quote Link to comment Share on other sites More sharing options...
Grangur Posted October 17, 2015 Share Posted October 17, 2015 Congrats on the New Old bass Day! I hope it lives up to the memory. It's also cool you've got chance for a "bonding activity". Good luck Quote Link to comment Share on other sites More sharing options...
Woodinblack Posted October 17, 2015 Share Posted October 17, 2015 When you say the middle soldered to each other is a dual gang pot? In which case that would be correct. The way of doing a blend is either you put one pickup on each side and take the output from the middle, or you do it with a dual gang pot with effectively two opposing volumes, where the centers are joined, you take the output from there, and each gang has the pickup one side and earth the other side, with both sides being wired the other way to each other. if it is a dual gang wired like that, it means the J pickup is disconnected, if it is single gang and the blend takes it down to no sound then it is shorted. Hopefully it is the first Quote Link to comment Share on other sites More sharing options...
Greggo Posted October 17, 2015 Author Share Posted October 17, 2015 [quote name='Woodinblack' timestamp='1445075437' post='2888584'] When you say the middle soldered to each other is a dual gang pot? In which case that would be correct. The way of doing a blend is either you put one pickup on each side and take the output from the middle, or you do it with a dual gang pot with effectively two opposing volumes, where the centers are joined, you take the output from there, and each gang has the pickup one side and earth the other side, with both sides being wired the other way to each other. if it is a dual gang wired like that, it means the J pickup is disconnected, if it is single gang and the blend takes it down to no sound then it is shorted. Hopefully it is the first [/quote] Yes it is a dual gang. The two middle lugs have a wire soldered to each other but this doesn't go anywhere else. The J bass wire was attached, but I have since ended up pulling it off by accident but I'll upload a picture shortly so you can get an idea what I mean on how blend seems to be wired. Quote Link to comment Share on other sites More sharing options...
Woodinblack Posted October 17, 2015 Share Posted October 17, 2015 If the middle is soldered together, it has to be the output, there is no other reason to join them. At a quick google image search for blend pots it seems the normal way is to put the inputs to the middle and put ground and out to alternate sides, but it doesn't really make that much difference (other than you have to swap the types around). But yes, sounds like something is not wired right with yours. It is notoriously difficult to get a good photo of guitar wiring! Quote Link to comment Share on other sites More sharing options...
Greggo Posted October 17, 2015 Author Share Posted October 17, 2015 (edited) Don't know if you can see the idea from this https://drive.google.com/file/d/0BykALQtqty0aanF3elNlbXkwdG8/view?usp=docslist_api The blue is bride +ve and red is neck +ve Edited October 17, 2015 by Greggo Quote Link to comment Share on other sites More sharing options...
Woodinblack Posted October 17, 2015 Share Posted October 17, 2015 ok - that makes no sense. If you took those two unattached pins to earth and connected your output to that joined middle it would work, but without that I don't even know what it is trying to achieve! Quote Link to comment Share on other sites More sharing options...
Greggo Posted October 17, 2015 Author Share Posted October 17, 2015 (edited) [quote name='Woodinblack' timestamp='1445084517' post='2888689'] ok - that makes no sense. If you took those two unattached pins to earth and connected your output to that joined middle it would work, but without that I don't even know what it is trying to achieve! [/quote] I have no idea either and probably just as well as the tone pot completely fell to bits when I unfastened it from body to check all wiring, so it has now all come out!I've just left a couple of inches of wire from jack to put on a terminal block on so can just rig it up easy enough to make sure bridge pickup does work OK. I'm going to order new pots for it and definitely rewire it vol - tone - 3w selector. Other than this issue, it is good to have the bass back. It was the first bass I ever played back in 1996 and I was so happy to have it gifted to me 4 years later. It is a bonding exercise to get it working as I remember it but hopefully with added benefits with a new wiring (the ease of three clicks - I never really saw the benefit of blend pot as I always ran it in middle or p) Edited October 17, 2015 by Greggo Quote Link to comment Share on other sites More sharing options...
Woodinblack Posted October 17, 2015 Share Posted October 17, 2015 The blend pot only really works if your pickups sound different from each other. If they do (like on my ibanez), it acts as a different type of tone control. I certainly wish the jazz had a volume and blend rather than two volumes. Quote Link to comment Share on other sites More sharing options...
Greggo Posted October 17, 2015 Author Share Posted October 17, 2015 Further developments to that story - the J pickup is actually dead. Also I realised that when I took that last picture of the wiring it looked odd because there was a wire attached to the two middle lugs of the blend pot that had come loose from playing about in the rats nest of wiring, so I think it was wired correctly after all and was a red herring because it had knocked it loose. Im guessing there's not much I can do about this now other than replacement J (which might be difficult because it's a 5 string bass with pickups closer to size on a 4 string. Quote Link to comment Share on other sites More sharing options...
Woodinblack Posted October 17, 2015 Share Posted October 17, 2015 Ahh, well thats a good reason for blend not to work! Quote Link to comment Share on other sites More sharing options...
Greggo Posted October 17, 2015 Author Share Posted October 17, 2015 After a bit of a struggle I got the jazz pickup out and only thing I notice is that the windings are still connected but one of them looks a bit loose away from the others but I'm not an expert on this... Can anyone shed any light...? Not best picture but can be seen on the lower. But I don't know if this is normal or not. https://drive.google.com/file/d/0BykALQtqty0aY2J6d0NwWTFHRWs/view?usp=docslist_api Quote Link to comment Share on other sites More sharing options...
Woodinblack Posted October 17, 2015 Share Posted October 17, 2015 Hard to tell, in itself it isn't too much of a problem except that the winds are normally tight, so if it is loose like that it may be broken. If it is, there isn't much you can do without quite a bit of careful work Quote Link to comment Share on other sites More sharing options...
Greggo Posted October 17, 2015 Author Share Posted October 17, 2015 (edited) [quote name='Woodinblack' timestamp='1445112287' post='2888935'] Hard to tell, in itself it isn't too much of a problem except that the winds are normally tight, so if it is loose like that it may be broken. If it is, there isn't much you can do without quite a bit of careful work [/quote] Update - coil wire has definitely snapped. Wouldn't know where to begin getting it fixed. Ah well. Edited October 17, 2015 by Greggo Quote Link to comment Share on other sites More sharing options...
pete.young Posted October 18, 2015 Share Posted October 18, 2015 What are the dimensions of the failed pickup? I might have something that would serve. Quote Link to comment Share on other sites More sharing options...
Greggo Posted October 18, 2015 Author Share Posted October 18, 2015 [quote name='pete.young' timestamp='1445164075' post='2889172'] What are the dimensions of the failed pickup? I might have something that would serve. [/quote] Ooh that's brilliant if you did thank you. Annoyingly I can't find a ruler but will have a search and post back. I know this particular model of Yamaha (1989 RBX5) was known for having 4 string dimensions but with an extra string. Quote Link to comment Share on other sites More sharing options...
Greggo Posted October 18, 2015 Author Share Posted October 18, 2015 Dimensions are: Length : 93mm Width : 16mm Cheers Quote Link to comment Share on other sites More sharing options...
MoonBassAlpha Posted October 21, 2015 Share Posted October 21, 2015 A lot of places will rewind pickups, it may even be repairable without a rewind. Worth looking into if you can't find one to fit. Quote Link to comment Share on other sites More sharing options...
Greggo Posted November 6, 2015 Author Share Posted November 6, 2015 Quick update on this for anyone interested got a cheap new replacement 4 string rail bridge pickup from eBay and this fits the bass fine and it's now back to full P/J capacity. The pickup was only 16 quid from eBay but it actually sounds great! The old one never sounded that good soloed was always used in conjunction with P but this one sounds fat soloed, very similar the J pickup in my old BB414. P/J tone with new pickup just fantastic now so ironically I'm glad the pickup was goosed so I could replace it! Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted November 10, 2015 Share Posted November 10, 2015 Good result! Quote Link to comment Share on other sites More sharing options...
cheddatom Posted November 11, 2015 Share Posted November 11, 2015 what pickup did you get? Quote Link to comment Share on other sites More sharing options...
Greggo Posted November 13, 2015 Author Share Posted November 13, 2015 (edited) [quote name='cheddatom' timestamp='1447247634' post='2906070'] what pickup did you get? [/quote] It was a pickup for a 4 string but was a rail j style pickup, apparently by a company called x-sound but I can't find any info on them. 6.5 kohms is the resistance rating. Nice tone soloed quite fat sounding, definitely the best J bridge tone I've ever had! Edited November 13, 2015 by Greggo Quote Link to comment Share on other sites More sharing options...
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