Floppy drive (DSDD) DOS compatability woes (are these drives ok?)
rescue at hawkmountain.net
Tue Nov 5 12:45:28 CST 2019
Been away for some time from the mailing lists.... getting back into
my classic gear again....
I have two of these Qumetrack 542 drives.
While testing my 360K drive collection (8 drives.... I must be slacking
:-) ...), 2 worked, 4 had issue (resolved with a good head cleaning),
and 2 (both of the Qumetrack 542 drives (I have two of them)) have mixed
results. My testing is on a Tandy 2500SX/33 using the Tandy straight
through cable and with the drives set do DS0.
I seem to have no issue with Dunfield's testfdc (using testfdc/x a:)
with these drives, doing SS and DD and getting 'pass' from testfdc. I
can also use his imagedisk program, go to the alignment section, and I
can track the drive properly up an down the disk.... it is just DOS that
can't seem to do it.
However, when I do a format a:, the drive will format through the 40
tracks, then instead of the heads returning to track 0 quickly, they do
these small stepping 'bursts' and DOS times out saying failure..... it
probably would have worked if DOS would wait 10 seconds or more for the
drive to move to track 0.
I've never seen behavior like this. I even tried an external power
supply in case the Tandy one wasn't up to driving the full height floppy
drive due to an aging marginal supply, but that didn't help anything.
I've now also had one of them shut down the power supply (a shorted
tantalum cap I'm sure).
I've looked through the manual on the drive, I've tried the HM, HS, and
no jumper setting for stepper motor power, same results in all cases.
I'm trying too determine if these drives are good. I'm planning on
using them in a Tandy Model III that is upgraded internally to a Model
IV, but I feel these are basic drives and should work in DOS fine too.
I hope someone has a clue, as I'm tapped out of them currently.
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