Lowering PS from 15 VDV to 12VDC

Those are standard computer PSU voltages !

If the supply is regulated, you might find the voltage divider that measures the output voltage against a reference and provides the feedback that sets the output. Changing the appropriate resistor might change the + and - 15 to + and - 12, but it may also lower the 5 volts to 5*12/15=4 volts. A safer approach would be to add LM7812 and LM7912 linear regulators to the 15 volt outputs to waste the extra

These parts are common as dirt and very cheap. If you load them with anything near their 1 amp capability, you will also have to mount them on heat sinks to keep them from overheating.

Changing

Yes, there is a variable resistor on the thing but it lowers the 5 volts also. I tried a computer powersupply but there were so many lines on it and I think it needs a load so it wasn't as easy to work with. I found this PS from a an extra DSL modem so that is what I am trying to work with. Or I could just buy the correct one. Well, either way now I know. thanks Russ

I see no link from this message to wherever that's mentioned...

is there a reason why a regular PC powersupply is unsuitable

that'll get yoy +5VDC and +12VDC at a number of amps and -12VDC at a few hundered miliamps.

sure it's possible to get +/- 12V from the one you describe but you'd be going half-way to building your own powersupply.

(snip)

Usually, only the 5 volt supply requires a minimum load. A

What sort of amps?

Put it in a case.

I see no link from this message to wherever that's mentioned...

Yes, I just wasn't 100% sure about the voltages so I sat at the computer for hours and I found this old SEC filing for the ITS company that was 200 pages long and as I read through the thing and I came across a name of a company that bought the first demo unit that I recognized. So I called them and they managed to dig the unit up and read me the PS requirements. They paid $6K for it in 1999. They are selling something similiar at