Univox Compac 2 electronic piano phaser ->guitar stompbox

[Red Favorite]

Hey folks...
I've had this Univox electronic piano collecting dust for a while:



At one point it was working, but some solder joints went bad & there are circuit traces that need repairing...it pretty much sounded like crap when it was fully functional anyway, so I've given up on fixing it...BUT, there is a phaser inside (on a separate board) that I'd like to turn into a stompbox if at all possible. Anyone have any experience in doing something like this? Can I just hook up a 9V battery to the power inputs? What about the level coming from the keyboard as opposed to a guitar, will I need to boost it? Cut it? I'm not really well versed in electronic mods, so any help/advice is appreciated. I'm also open to suggestions about something cool to do with the rest of the keyboard...

Thanks!
Jeremy

[japmn]

HA! I had one of those too. I left it on top of the dumpster when I moved.

I would guess you could yank the phaser out, it should have 2 power lines (the voltage of which you can measure with multi meter) a pos in and a pos out and most likely got ground from physical anchoring or it may have wires.

Just wire it up to a DPDT switch.

[Red Favorite]

HA! I had one of those too. I left it on top of the dumpster when I moved.

I would guess you could yank the phaser out, it should have 2 power lines (the voltage of which you can measure with multi meter) a pos in and a pos out and most likely got ground from physical anchoring or it may have wires.

Just wire it up to a DPDT switch.

Thanks for the quick reply! Got it out of the case & wired up a 9v battery clip to the + & - inputs on the board (I don't have a multimeter to check voltage), and soldered a couple of 1/4" jacks to the input & output, but no sound. Am I right in thinking that it won't work until it's properly grounded (i.e. in a metal case)? I'd like to make sure it's actually going to function before I spring for a project box, is there a way to ground it temporarily while I troubleshoot?

Thanks again,
Jeremy

[Nate Dort]

Putting it in a metal case to "ground" it isn't going to do anything. Are you sure that thing runs on 9V? It may take a bipolar supply, something like + and - 18V.
You really need a schematic, or at the very least, a multimeter to see what voltage(s) is/are being fed to that board from the main power supply.

[Red Favorite]

Putting it in a metal case to "ground" it isn't going to do anything. Are you sure that thing runs on 9V?

Nope, not sure at all. I was just kind of hoping it would work. Like I said, I'm not an expert...

It may take a bipolar supply, something like + and - 18V.

I think my friend has a multimeter, I'll borrow it & check the voltage...but say that was the case, are there any links you know of for something like that? I found this, but would prefer something premade if possible...

Thanks,
Jeremy

[Nate Dort]

Assuming it takes a bipolar supply, you may be able to get away with running it at +/- 9VDC, which you can do with two 9V batteries in series. Completely depends on the circuit though, and this is all speculation. Otherwise you'd need 4 batteries to get +/-18VDC in a simple way without external components.

Or, find a wall-wart that puts out +/-18VDC and hook that up. I've seen those around.