15 Jun
2010
15 Jun
'10
10:27 a.m.
On Tue, 15 Jun 2010, Philipp Hachtmann wrote:
Well, erasing takes place *after* writing. The R/W head writes the data
and the erase head then erases the borders of the just written data.
The error just sounds like the one I had in my RK05 drive. I could read
all my packs without any errors, but writing the lower side was very
unreliable. Tests showed that I could write (and read back, of course)
data from track 0 up to 127. Starting at track 128 I just had lots of read
errors. The maintenance manual revealed that the write current is reduced
starting with track 128, so that gave me a clue. Swapping the cables from
the upper and lower head moved the errors from the lower to the upper side
(logically, i.e. from the software point of view), so the fault was not in
the R/W amplifiers. It could only be a defective R/W head. I then changed
only the lower head, and the drive is working fine since then.
I suspect that the head had shorted windings or something like that. It
otherwise looked fine. It is possible that it had crashed sometimes in
the past before I got the machine.
Christian
I think
that's unlikely. There is a tunnel erase head which essentially
wipes out any old data that might be picked up by the read head.
You mean that the
erased trace is guaranteed to be broader than the area that
can be sensed by the read head? Do you know if the heads are good? I've had
at least one RK05 head that
tested OK electrically, looked clean, but which procuded no signal
Oh, I cleaned
them. And they look white. And I actually CAN read and write
with both heads. But there are errors from time to time. And the error
frequency seemed to drop with every time I format the pack... Perhaps it's
something at the write side... No idea.
I'll grab some heads and throw them at the drive. Then I'll try again.
Currently I have to find a new blower for the unit 0 RK05 of my test system.
It shorted and burned yesterday while playing with the rotten drive.