6 Feb
2008
6 Feb
'08
3:45 p.m.
On Tue, 5 Feb 2008, Jerome H. Fine wrote:
My guesses on these, based on the RX50 scheamtics...
While I never had any problems with the RX50, I
found that the big
advantage was the extra capacity!
The big problems I heard about regarding the RX50 were:
- Drive speed tolerance was looser than that required to format media,
which is why the Rainbow was shipped without a formatter.
The spindle motor is similar to that in many other drives of the time, a
DC motor with a coupled tachogenrator. Unlike most other drives, the
control circuit doesn't use the LM2917 chip, but I see no reason why the
DEC design shouldn't work well.
_But_ IIRC the RX5 0fromat was 10 512 byte sectors per track. That's
tight, and it might well need an accurate spindle speed (in particular
one that's not running too fast) to format a disk.
- Hub reinforcements could allegedly damage the
plastic fingers that
held the diskette hub.
It's been a long time since I've been inside an RX50, but I see no real
difference between the hubs on an RX50 and those on other drives.
- It was possible to step the drive beyond track zero.
Yes, Unkike most other drives, the RX50 stepper control circuit is not
inhibited by the track 0 signal logically ANDEd with (direction = out).
It's quite possible to step the heads out beyond track 0. Whether this
causes any real prolems I don't know.
-tony