Need Help with Mini Q-tron Mod

[Zachass]

Finally got the parts in to put a volume control in my q-tron. Following the directions in this thread http://www.talkbass.com/forum/showth...60#post3601160
I've got it pretty much working, just need to ground the pot now. It says to wire it to the pot cover, but I'm having problems getting that to work, will someone explain exactly what I have to ground it to on the pot or offer alternate grounding solutions? Thank you.

[niftydog]

Clean the bejesus out of the pot casing first - they are often covered in a yellowish lacquer that makes soldering utterly impossible. You want it to be bare metal - use sand paper if you have to.

You'll need a reasonably high powered soldering iron to do this successfully. If you have to hold your iron on the pot casing for more than 5-10 seconds before the solder starts to melt, then you run the risk of destroying the pot by applying heat for too long. Basically you want something powerful enough so that you can get the whole thing done in about 15-20 seconds, preferably much less. Use a big tip and make as much contact between the tip and the pot casing as you can.

This is one thing that most first time DIYers (and even some old-timers!) stuff up, so don't be surprised when you do!

[bongomania]

Yep, I wrecked a fair number of pots before learning to scrub and/or sand them first. Just to clarify, the easiest and best location on the housing is just the big round top surface.

[Zachass]

Thanks guys, I got it working, though the solder job is pretty ugly so I may try it again tomorrow depending on how it looks after a nights sleep.

[Zachass]

Ok so I had everything working two nights ago. I had soldered the ground wire from the first pot leg to the wrong side of the pot, the side where the shaft sticks out (and what an ugly solder job it was). However I was getting some funky sounds out of the q-tron, though the connection would cut in and out every once in a while. So to fix this problem, I desoldered that pot and all the wires, switched it with another pot of the same value to save time, soldered the ground wire to the bottom of the pot casing (the big round side that says alpha, opposite to the pot shaft side) and resoldered the other two wires in the proper place to the solder lugs on the new pot. Now, the circuit works, theres no static, but
the funk is gone. The volume pot doesn't seem to be doing anything to the actual signal level, and the whole thing sounds more like a boost with a little grit than an envelope filter. Once again, I need your help. I can post sound clips if necessary.

[niftydog]

Ok, run through exactly what you've done again!? No wait, don't tell us everything that went wrong - that just confuses things! Just tell us how it was before you started, and how it is now.

One thing that springs to mind is that a volume pot should have a ground connection to one of the outer terminals - you haven't mentioned it so I'm not sure if that's an issue or not.

[ianzeds]

ok i've been pretty stupid when fitting a centre negative power socket and knackered my q-tron, now the drive control acts like a speed setting on a phaser/flanger, any ideas on what i should try to replace to fix this?