HP 88780 tape loading questions

[John Foust]

I tried the Overland Data 5622 I bought; it seems to have big troubles.
On power-up, "Alert" blinks and it won't load - none of the buttons work.

I've temporarily given up on the M4 9914 and exploring the HP 88780.
It loads a tape almost always.  It catches on the takeup reel, whips
into high-speed mode, then 

Test 0 passes.  I've run a few of the most interesting interactive test 
sequences.  NVRAM, timer, DAC, ADC, tach, motor loop, tension limit 
and sensors, speed encoder, tape sensors, BOT/EOT sensors all OK.
Test 1 with a scratch tape fails within test 165 "load tape", 
followed by "ERR 60".  

Bitsaver's 7980 manual on page 5-119 (PDF pg. 186) says error 60 is 
"tracks with gain too low and too high during autocal."  Does this
mean I need to clear the NVRAM and run the "test 99" calibration?  
I haven't changed or recorded the NVRAM values yet.  Should I bother?

Anyone have experience with http://www.comco-inc.com/ ?  They're only
a few hours away.

- John