TU-81+ and KLESI help sought

Thanks to the two folks who responded on my KLESI-UA stuff! The particular TU81 manual I was pointed to wasn't on bitsavers. It pretty much answered all my questions so far. RT11 at least sees the board at 174500 now (thanks to switch settings!). When the system boots it tried to do R MSCPCK which hangs now... probably not a good sign. If I break out of the bootstrap before that, a copy to MU0: hangs as well. Hrm.... ZTU2?? isn't happy though, I tried two different KLESI-UA's with no different results. Both halt during test 1. I guess first question is the cable. From KLESI-UA to bulkhead I had a 70-18652. The round DD50 from the tape drive plugs in to that. In looking at the docs provided, it appears I should be using a 70-19923. Aren't all these just 50 pin straight through cables, or is there a difference that is catching me? Thinking it was just 50 pins straight through with a DD50, I also tried a 70-20691 which also appears to just go straight to the DD50. Same problem with all of them. Is this supposed to be a specialty cable? Failing that... either both KLESI's are dead, or there's something seriously amiss with the TU81 itself. I shall dig into the TU81+ manual given above and see I can figure out the troubleshooting steps. Advice appreciated :) Thanks! Jay West