Please help me not fry this Trident VU/PPM meter

First, thanks to everyone on this forum. I have been lurking for a while and have enjoyed learning from the people here.

I am working a box to go after two matrix channels on a PM-2000 that will be the summed output for recording and monitoring. I'm basically hoping to use the program buses as subs. The idea is to have an attenuator (my power amp has none), a mode switch like the one on the Goldpoint site (stereo, reverse, mute, mono, l-mono, r-mono) and... you guessed it... a PPM meter.

I picked up a pair of VU/PPM meters from a very nice gentleman that might have possibly come from a Trident A range console. The drivers look like re-branded Ernest Turners since they are labeled ET903. I pretty much don't know what I am doing so I am looking for any advice on:
1) What voltage to apply? I really dig the look of these meters and don't want to blow them up.
2) Any ideas on how the unit was switched between VU/PPM mode. There are three poles on the middle left pic of the driver... this is where I would start if I wasn't afraid to apply voltage. :sad:

Any help you could provide would be greatly appreciated. Thank you.

Jay Ridgeway

So... my Mouser order came in and I figured I would wire up a power supply this weekend and do some testing. Does anyone see a problem starting with +/-15 volts and working my way up +/-24? I have very limited experience. Thank you.