How to test an L2000 preamp

[narcdor]

Hey guys, I'm new here so feel free to link bomb me if this is covered elsewhere, but...

I have in my hands a G&L bass preamp Rev 1.0 from an early 90s L2000. It was provided with no guarantee it would work, and I would like to know without completely rewiring the bass what is the easiest way to determine if it still operates?

For instance I have a spare jack, P pickup, and battery. Is there some simple setup using this or just a multimeter I can use to check it's even operational without wiring up switches etc. I tried to understand how to wire up just one pickup but the exceedingly complex schematic with two passive tones before the volume and three switches is truly beyond me. I've only wired up a P bass before for example!

I look forward to your knowledgeable responses.

[narcdor]

Oh whoops, I didn't realise there was a separate bass forum, I've posted over there as well. I expect with active preamps being more common in basses I'll get a hit over there.

Not saying you guys can't still help though, feel free!