Wiring Problem on Warwick Bass!

[Funkyman]

Hello to all, and thankyou in advance. First, the bass specs are:

-Neck Pickup. Single > Bare, Red and White

-Bridge Pickup. MM Humbucker > Bare, Green, Black, White, Red

-Bass, Mid, Treble, Stacked Vol/blend (With push/pull active/passive switch), 3 Way switch MM Pups selector

I Have a problem, i changed the preamp on my bass (Warwick Streamer Jazzman) but i didn't like it, so i went to reinstall the old pre back, and everything is soldered well acording to the diagram (attached below) except the grounds.

The main problem is that all the grounds shown on diagram doesn't specify where they should go, and as a result, Vol/Blend pot and 3 way switch works fine as they should normaly, BUT bass-mid- and treble Pots are completely inoperative, and so far i have zero noise or hum.

Things i tried (just guessing, without any knowledge of how grounds should be connected):

-I made sort of a "main" cable which has several little wires going separately weld to each ground points specified in diagram, then i weld this main cable to the third bigger leg of the output jack - NO AVAIL

-I did a separate wire from each ground point, to the jack - NO AVAIL

-Connected each ground point among themselves (all pots and switch) - NO AVAIL

So at this point, the bass sounds weak, and witout the 3 EQ's!

Sorry for bother you, and i hope you can help me! Thankyou very much!

Diagram from MEC Pickups:



Stacked Vol/Blend Pot:



Bass, Mid, and Treble pots:



Actual pic of the Electronics:

[Jazz P Bass]

What you have to keep in mind on these preamp setups is the fact that the battery ground is usually "switched" on when a plug is inserted.
Without having the schematic for the preamp board, it is guess work from my end.
The hint is the "stereo" jack. Tip, Ring, Sleeve.
When you insert a mono plug into the jack, ring & sleeve are connected together.
The ring wire is indicated by pin 14 on the preamp board.
I have a feeling that that wire goes to the black wire of your battery.
This will turn the circuit "on" when a mono plug is inserted.
The grounds that you connected to the pots are not circuit related.
They are simply grounding the potentiometer cases.
The circuit grounds of the pots go to the preamp board.
Where they are most likely routed through the jack sleeve ground when a mono plug is inserted.

[David Schwab]

What did you disconnect when you removed the preamp the first time? You didn't unsolder all the wired from the pots, did you?

[Funkyman]

What did you disconnect when you removed the preamp the first time? You didn't unsolder all the wired from the pots, did you?

Hello David,

No, i left bass, Mid and Treble pots wiring soldered as it was, I disconnected everything else, Vol/Blend pot, all grounds, jack and switch, obviously with stupidity included (not taking note of this).. so now i reinstalled everything all i could, and at this moment the bass is sounding, everything works, except Bass Mid and Treble Pots... they are totally inoperative... Possible solutions?

Thanks

[Funkyman]

I have a feeling that that wire goes to the black wire of your battery

Thankyou very much! I would try this and let you know!

[Funkyman]

Tried everything.. Still the same Everything is working except Bass-Mid-Treble pots..

[Jazz P Bass]

"Tried Everything"?
O/k. Let's try troubleshooting.
Have you verified that any of the ground pins of the tone pots do connect back to the input ground lug?
Is the preamp board getting voltage from the battery?
Is the opamp getting this voltage? (pin 8 is +/ pin 4 is ground)
Are the opamp output pins (1 & 7) sitting at roughly half of the battery voltage?
Is the opamp getting signal?

[David King]

I agree with Jazz P, check the output jack wiring. The shortest jack lug is usually the tip i.e. hot signal connection. The battery black wire goes to the next shortest lug.
Check battery for voltage?
Faulty 9V battery connectors are the cause of most active system problems.
Warwick uses very low quality jacks, I've replaced dozens of them over the years.
Warwick basses in general have the lowest quality to price ratio.