[sgroup] S-10 SysEx bafflement

I picked up a busted S-10 for pretty cheap, and I'm trying to recondition it. I was able to replace a couple of caps and get most functions working. I can sample and play back, I can use it as a MIDI controller, data sent to MIDI IN shows up on MIDI THRU... The QD has a melted belt but I have replacements on the way. Until I get that working I can't get through the diags far enough to be 100% certain that MIDI IN works all the way to the CPU.... I was going to see if I could get some of the SysEx samples from the old archive (thanks folks!) to download via MIDI, but I'm not having a lot of luck. To start with, the manual doesn't mention hitting ENTER after selecting one of the 4 SysEx modes. So I found that entirely by accident. But I'm still having no luck, and I'm hoping maybe someone here has experience to know what else may be omitted (or overlooked) in the manual. Here's my setup: macbook pro, generic USB-MIDI interface, running a tool called SysEx Librarian. It reads the archives just fine, lets me view them and the data conforms to the spec. To dump, you select which MIDI port, and hit "play" and it sends the messages downstream (blindly). On the S-10 to prep I select bank, MIDI, confirm that I'm actually on channel 1 (where the dumps come from) and that Exclusive = On. Then I hit F1+MIDI, FWD twice to get to "one way sample data receive" (since I can't do handshaking), and hit ENTER. At this point it says "Wait for sample data" or some such. I then hit play on the librarian...but the S-10 screen stays at Waiting. I've tried hitting ENTER again after sending the data (does nothing), hitting the bank key again (cancels)....played with a few other keys but nothing seems to be doing it. I can't help but think I'm missing something else, and/or that it should say something when/if it actually starts receiving data. I'm pretty positive I'm using the right port on my USB MIDI interface, but I tried sending to the other one just in case, and got the same result. I'm also a little concerned that the spec mentions a 20ms wait between frames of SysEx data, and I don't know (not sure how I could tell) if my librarian is honoring that. Has anyone done this recently enough to remember if/what magic incantation is still necessary? Anyone had any luck running the windows tools in a virtual machine? That's really my next line of testing. That, and getting the QD drive working so I can get it past that part of the diags and into the part where it tests MIDI. Thanks....