mewis Posted March 11, 2019 Share Posted March 11, 2019 (edited) Hi there. I was wondering if anyone could help we with repairing my Warwick thumb bass as I have struggled to find a wiring diagram for it. On inspection I found that it looks like the bass has had repairs in the past. There was a loose wire that looks like it should go from the jack to the volume pot. This wire has a outer and inner part but I'm not sure how this connects up. Also I thought that there should be ground going from the jack but there does not seem to be. I have attached some images that hopefully explain this. any help would be very much appreciated Edited March 11, 2019 by mewis Quote Link to comment Share on other sites More sharing options...
itu Posted March 11, 2019 Share Posted March 11, 2019 In the first picture the ground wire is missing from the output jack. Probably the battery wire, too. In the second picture I can only see that lower left corner, where the (Volume?) pot has no wire in the lowest leg on top of the red wire. There has been something soldered to it. The black wire from the output jack - where does it go? That third picture has a shielded wire. The inner one is most probably signal and the outer mesh is a ground. Where from, where to? From the fourth I may see (?) that the missing wire (referring to the second pic) and the lug are soldered to another lug of the pot. Is this Volume? The output needs to have three wires (in case of active bass): Ground, -9 V and the connection to the preamp that connects the 9 volt battery minus to the Ground (and the preamp starts to work). Naturally the preamp needs the 9 volt plus connection. If you take some time, try to find which are the signal cables from the pickups. They should go to the Balance/Blend pot and then to Volume. From Vol the signal goes to the preamp input. There should be few wires from the preamp to B&T (dual?) pot. Then you need a few wires that are connected to the ground. Every part has something to do with the ground, so take your time and find the connections. Use permanent pens or tiny paper stickers to name them and you can conclude the signal path. Basic idea is: pickups - Blend - Vol - preamp (B&T) - output Bass and Treble are in a "side chain" so the preamp has one signal wire going in and another going out to the output jack. It is probably close to this one (or another similar setup): https://shop.warwick.de/en/Parts+for+Instruments/Parts+for+Basses/Electronics/MEC+Active+BEC+2+Electronics+for+active+Pickups+-+_Vol+PP+_+Bal+_+T+B_ https://shop.warwick.de/en/Parts+for+Instruments/Parts+for+Basses/Electronics Hope this helps. Quote Link to comment Share on other sites More sharing options...
itu Posted March 11, 2019 Share Posted March 11, 2019 It does not look impossible at all, you just have to find out the signal path and it will open up. Someone able to do nice solderings will be your dear friend. And sorry, I certainly live too far from you. Quote Link to comment Share on other sites More sharing options...
mewis Posted March 12, 2019 Author Share Posted March 12, 2019 Itu, thank you. I think the shielded wire went from the jack to the volume pot, although I'm not sure what I do about the shield part. weirdly there were no other loose wires in there so not sure where the jack to ground has gone. Quote Link to comment Share on other sites More sharing options...
itu Posted March 12, 2019 Share Posted March 12, 2019 A tiny wire may just disappear in the air (to tape, under some part or so). Now draw the schema to understand the signal path. Then find all wires and name them. Then it is easy to understand what is happening down there. Quote Link to comment Share on other sites More sharing options...
dyerseve Posted March 13, 2019 Share Posted March 13, 2019 IIRC that shielded cable will be the output from the volume pot to the jack. The inner part of the cable(carrying the signal) goes to the inner tag of the jack and the outer part(providing the shielding) can be grounded anywhere - looks like it was possibly earthed on to the case of the concentric treb/bass pot Quote Link to comment Share on other sites More sharing options...
dyerseve Posted March 13, 2019 Share Posted March 13, 2019 This should be the correct schematic for your Thumb: 60003a.pdf 2 Quote Link to comment Share on other sites More sharing options...
mewis Posted March 14, 2019 Author Share Posted March 14, 2019 Brilliant. Thank you for all your help Quote Link to comment Share on other sites More sharing options...
Jabba_the_gut Posted March 16, 2019 Share Posted March 16, 2019 I’ve got a Warwick preamp in a box somewhere that I believe came from a Thimb bass ( two stacked pots and one single - one of the pots is also a pull switch). I’ll take a couple of pictures when I get home and post them on here. Cheers Jez Quote Link to comment Share on other sites More sharing options...
mewis Posted March 17, 2019 Author Share Posted March 17, 2019 19 hours ago, Jabba_the_gut said: I’ve got a Warwick preamp in a box somewhere that I believe came from a Thimb bass ( two stacked pots and one single - one of the pots is also a pull switch). I’ll take a couple of pictures when I get home and post them on here. Cheers Jez That would be amazing, thank you Quote Link to comment Share on other sites More sharing options...
Jabba_the_gut Posted March 17, 2019 Share Posted March 17, 2019 My pre-amp looks a little different to yours but here's the pictures anyway: Lett me know if you want any close-ups of any parts of this. Cheers Jez Quote Link to comment Share on other sites More sharing options...
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