I'm a day late on this one, but with the beautiful weather in the Northeast, been earning points with the XYL so that I might have a little peace over here in the Mancave. The D500 off ebay, which I have to thank George for posting out here, arrived yesterday. I've already been in touch with Glenn, Dennis and of course Joe to source parts needed to WOPL this beast. While there is no WOAD Backplane for this unusual beast, Glenn will be building the backplane in Full Complimentary mode - from scratch, as he has done so often. My hats off to you, Glen! When I look at his work, it reminds me of a plane of core storage that was hand-stitched by technicians for the 360 mainframes .... precision and persistence.
Anyhow ... some pictures. I will start a thread when I get around to tearing this down and will try to be vigilant on the rebuild.
QUIZ Bonus Question: Seller said one channel was not working. Anybody care to hazard which one? Oh - and here's a hint, it was not the one with 14A fuses in the B+ and B- sockets!