Ibanez TS9 drive knob not working.

[aeromike9]

I am trying to fix an Ibanez TS9.  The Drive knob does nothing, but everything else works fine.  I opened it up and nothing is connected to Lug 3 on the Drive Pot.  It looks like it was at one time connected to Lug 2, but may have come loose. 

Also, Lugs 1 and 2 of the Drive Pot have wires connected to them but both Lugs are connected together with a big blob of solder.  So this means that if I connect Lug 3 to Lug 2, all the Lugs of the Drive Pot will be connected together which does not sound right.

I tried looking at a schematic, but am not to good at reading those things.

Thanks for the help!

[aeromike9]

Well I desoldered  the two wires on Lugs 1 and 2 that were all connected with one big blob of solder, and soldered them back into place separately.  The Drive knob now works!!!

The pot was touching the inside of the enclosure which was possibly causing it to short out, but how Lugs 1 and 2 got all fused together with all that solder I don't know.

Lug 3 still has nothing connected to it, is that right?

[MmmPedals]

The third lug does not need to be connected to anything.

[Electron Tornado]

This is not to be condescending by any means, but learning how to read a schematic will help you immensely.

If I understand what you are saying, you had two problems going on. If the pot lugs are touching the enclosure it will create a short to ground the pot and the control won't work correctly. If you had lugs 1 and 2 connected with a solder bridge that would also cause it not to work correctly. The pot was connected in parallel with what was essentially just another wire.

Here are some links that will help you understand what was going on and why the drive control wasn't working. Concentrate on the discussions of non-inverting op amp gain.

http://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-gain.php

http://talkingelectronics.com/projects/OP-AMP/OP-AMP-1.html

http://www.williamson-labs.com/480_opam.htm

[aeromike9]

Thanks guys for the replies.

I am starting to learn how to read schematics, but sometimes get confused when schematics for the same circuit are done differently.

Thanks for the links, much appreciated.