8 Sep
2006
8 Sep
'06
4:20 p.m.
I did some basic diagnostics on the system. First, checked the
superficial stuff like the cable. The Berg has a strain relief attached
and all wiring looks solid at that end. Also checked the head lock
which was indeed in the lower (free) position however I observed the
head suring loading and it does indeed retract properly ... when the
LOAD key is out the heads retract immediately to the parked (fully
retracted) position. When a fault occurs, heads pull back as well.
True, the unit was transported without the head lock in place - any
ideas on possible misalignments?
It's not a nlignment problem (the RLs, being embedded servo drives, are
very tolerant of alignemtn), it's more that if the heads bang into each
other, or worse still crape across a non-rotating disk, it can damage the
heads.
However, the fact that your drive finds cylinder 0 and goes ready implies
to me that the heads are flying and that they're reading something
namely the outer guard band and the survo bursts on cylinder 0).
When the BOOT switch on the limited-function panel (or the BOOT key on
the console) is pressed, the FAULT light blinks momentarily, the READY
light goes out momentarily, and the disk is restored to the original,
ready, state. When the cartridge is loaded, the heads move from the
parked state to engage the disk. During the fault the heads pull back
to the parked state and are then restored to the disk again.
Now that bothers me. IIRC, for some faults the drive does retract the
heads to protect the media., This certainly shouldn't happen during a
bootstrap.
What I would do is to get the appropriate printset (the first RL01s have
a logic board that's RL01 only, later ones have a board that can be used
in RL02s as well -- there's a jumper to cut or install -- you may
actually need the RL02 printset, therefore), and find out what can cause
the fault lamp to go on (from what I rememebr there's effectively a big
OR gate for this). Then grab a logic probe and see which input(s) of that
is/are going active. And progress from there.
-tony