Brian Brikon diskette drive tester

I purchased one of these units on eBay and it seems to be working - modulo a few early-80s tantalum caps that went up in smoke. The tester relies on an attached printer to record test results, which are displayed only fleetingly on the front-panel display. Unfortunately it did not come with the printer and I cannot find any information on line. Does anyone have information on this? Is it serial? Parallel? The onnector is a 20-pin, 0.1" DIP header on the rear panel. The tester supplies printer power on a small 3-pin Molex connector. I can probably trace this out on the internal logic board, but thought perhaps another list member owns one of these and can elaborate. I'm also trying to find the manual appropriate to a base Model 723 tester. The one floating around on the net is for an upscale model (723-4M). While there are a number of similarities, I'm running into just enough behavioral difference to make it worth finding the correct docs. There's also a programming and setup "worksheet" document that has not surfaced anywhere.