Well, I've removed the diplexers from the line and completely realigned the dish. I had to readjust everything, including getting the mounting post level. Everything was close, but not quite right. I guess the installers figure close is good enough.
Anyway, almost everything has signal strength readings in the high 80's to low 90's on all 3 satellites now. Also, a noticeable, but small, difference in the signal strength levels between the odd and even transponders is gone. Transponders 22 and 24 on 119 read 85 and 63 (yes, it is the weakest reading of all the active, non-spot, transponders on ANY satellite) respectively. The next lowest reading is 81 on 119, transponder 28. Transponders 31 and 32 on 119 both read 92 now and transponder 27 is the strongest on 119 at 93. The strongest reading on 101 is 94! I'm actually getting weak readings, most of them in the 30's, on almost all spot transponders now, so I expect the dish is really locked in!
I just can't wrap my brain around how the multi-switch could be causing the cycling between OK and DEAD on THESE 2 TRANSPONDERS ONLY!! and ALL 4 LINES FROM THE DISH/MULTI-SWITCH ARE BEHAVING IDENTICALLY!!!
Both transponders 22 and 24 were looking reasonable before I started working on the dish today. Over the last hour (when I got the readings above) and now, the readings on 22 and 24 have changed to 85 and 37 respectively! Note that only 24 has changed, and it has changed quite a lot! It looks to me like nothing has changed in regard to this problem. The only thing left to try is replacing the LNB/multi-switch!!
Overall, a good exercise with a good result today, but the real problem still isn't solved!