Sting ray actives NOT active. Help!

[rosssurf]

A freind brought me a sting ray bass, from the mid 90'sto set up and fix. It was not producing any output. It seems the white wire had come off the circuit board. I reinstalled the wire and the bass worked passively. I then installed a 9V that was on the weak side measuring a 8.5v and did not get any change in sound. The passive quiet sound was there but it does not seem to be active. The out put does not increase with the battery in. I am getting power to the board from the battery, all componets look clean and ok. I have double checked with a wiring diagram and all seem to be wired up correctly.

Can anyone help me figure why this bass is only producing a NON active sound?

[David Schwab]

Check that the battery is actually getting switched on. This just happened to me last night, when coincidentally I was installing a Musicman clone preamp into my Ibanez. I got no sound, except for a very weak signal. I turns out my battery clip's connection to output jack was bad. I resoldered it and it worked as expected.

So plug the battery in, plug in a jack, and take a reading from where the battery connects to the circuit board (the red and black wires) and see if you are getting voltage. If not, check out the output jack and battery clip.

Also, that bass cannot work passively, you are just hearing signal bleeding through the preamp.

[rosssurf]

Thanks David, heading off to a gig i will look into it tonight. Thanks !

[rosssurf]

stingray preamp issue

The jack is the older style, and if I understand correctly, it does not require a plug to be inserted to send 9v to the board. With the plug in or out I am indeed getting +/- 9v at the red wire insert on the board as well as over to pin 8 on the op-amp. I am getting 4.5v on pin 5 also. I think this is as it should be. I am also getting ground continuity from pin 4 on the TL062 chip as well as on the ground wire, jack, pots ,and bridge.....hmm?

I removed the 2 pickup wires from the board, (black and white)and got a measurement of 1.9K (1,900 ohm) resistance. This seems exceptionally low, but perhaps is in line with the ohms of a pickup such as this? Can you confirm?

I did have the pickup out and the coils exposed to clean the pole pieces and none of the connections looked suspect.

FYI- If it helps narrow down the problem, the signal is very weak but the volume pot acts as it should but no other tone controls seems to be affecting the sound. ( There is NO change in sound with all of the other 3 pegged or turned all the way down.

any other suggestions? Thanks David ( and anyone else who cares to respond.

[David Schwab]

The jack is the older style, and if I understand correctly, it does not require a plug to be inserted to send 9v to the board.

Unless it's one of the very first basses with the regular mono plug, which had the battery on all the time, it does switch on the battery. Since your preamp is using the TL082 and not the LM4250, it would be switching on the battery.

With the plug in or out I am indeed getting +/- 9v at the red wire insert on the board as well as over to pin 8 on the op-amp. I am getting 4.5v on pin 5 also. I think this is as it should be. I am also getting ground continuity from pin 4 on the TL062 chip as well as on the ground wire, jack, pots ,and bridge.....hmm?

Maybe the op amp went bad?

I removed the 2 pickup wires from the board, (black and white)and got a measurement of 1.9K (1,900 ohm) resistance. This seems exceptionally low, but perhaps is in line with the ohms of a pickup such as this? Can you confirm?

The pickups has two coils of about 4k each, so in parallel that would be about 2k. So that's a normal range for a Musicman pickup.

I did have the pickup out and the coils exposed to clean the pole pieces and none of the connections looked suspect.

FYI- If it helps narrow down the problem, the signal is very weak but the volume pot acts as it should but no other tone controls seems to be affecting the sound. ( There is NO change in sound with all of the other 3 pegged or turned all the way down.

any other suggestions? Thanks David ( and anyone else who cares to respond.

Are there any lose parts on the circuit board? Or swollen electrolytic caps?

[rosssurf]

Thanks for your help David, I ended up putting in a new TLO72 and it now works fine.