May I please get some help in troubleshooting my Warwick thumb?

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Hey!

First time poster here because I really, really need some guidance and help and I didn't really know where to go before running away to a guitar tech with my bass.
I am an owner of a Thumb BO 6 and everything was fine until some weeks ago, where my Thumb bass started to buzz the kinda noise you would hear while your bass is unshielded/ungrounded.
I did the shielding, grounding and soldering and everything seemed fine...

Except that when I touch the pickups (the plastic, not the height screws) the buzzing came back.
What do I do about it? Why is the buzzing back while touching the pickups?

More info:
- Both pickup cavities are shielded and grounded to the jack.
- The electronics cavity is shielded and grounded to the jack.
- When I touch the strings/pegs/any part of the bridge/jack/pickup screws, there is no buzzing.
- The bridge ground wire is fine, I checked it by taking out the bridge.

Some photos:
IMG_20210716_120826.jpg

IMG_20210714_203430.jpg


By the way, there is a connection between the cover plate shielding and the electronics cavity shielding.

IMG_20210714_155900.jpg


So here I am. Hopefully someone can help me out, I will gladly accept any kind of help and questions.
I might not be very experienced in electronics but I will listen and provide as much information as I can when asked.

Just help a fellow girl out, pretty please!
Thanks and have a nice day.
 
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DiMarco

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Hi Katoosie, welcome to the forum!

Is it only buzzing while touching the pickup covers or when touching both strings and pickup covers? Is the bridge grounded properly too?
 
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*edit.. i didnt read your post properly. I would say that somewhere there is a ground issue. Have you checked the connection of the bridge wire and if it is solid to the bridge and the jack (or wherever they ground it). Warwick use a shielding paint that is black so it might not look shielded but it was already. The only other thing is that it is something in the preamp system...check connections, change battery, check for dodgey solder joins.

Sorry dont feel very helpful but worth a crack
 
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Hi Katoosie, welcome to the forum!

Is it only buzzing while touching the pickup covers or when touching both strings and pickup covers? Is the bridge grounded properly too?
Only the pickup covers, everything else grounds the bass. The bridge is grounded.
*edit.. i didnt read your post properly. I would say that somewhere there is a ground issue. Have you checked the connection of the bridge wire and if it is solid to the bridge and the jack (or wherever they ground it). Warwick use a shielding paint that is black so it might not look shielded but it was already. The only other thing is that it is something in the preamp system...check connections, change battery, check for dodgey solder joins.

Sorry dont feel very helpful but worth a crack
I will be taking out my soldering iron and trying to redo some joints. I know it is covered in black paint but I thought I would copper shield it on top in case there was something off there.
 
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Welcome to the club Katoosie, and let us know of your soldering skills!! If it is not the points of the cables to the balance pot, the chase will be on !

How is the bridge grounded? Is there a thin wire? And if so, how is this connected?
 

golem

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I strongly suspect that when you “fix” something, you’re not correcting a flaw, but you are having an effect just by slightly changing something.

I believe you’ve built a weird capacitance situation, especially by putting shielding over shielding (foil over paint). The plastic PU covers are holding a charge and when you touch them you trigger a flow, and a buzz. Other than undoing most of your additional shielding I don’t think there’s much you can do about it.
 
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