26 Jan
2014
26 Jan
'14
6:08 p.m.
On 01/25/2014 07:30 PM, Daniel V. Mackey wrote:
Assuming you can get one with the right specifications, I would always
bey a double-sided alignment disk. You may need it later for DS drives.
However, in 99% of floppy drives you cannot (officially) adjust the heads
sparately. You align one side, check the other, if the latter is not
aligned properly yuo have to repalce the head assembly. So a single-sided
alignment disk is perhaps not a mjor problem,
Ok, which disk would I purchase then?
I'd first check with Accurite, but 208-40 seems to be a fair match. The
1541 is SS, 48 tpi, IIRC. The 1571 is double-sided.
It helps if your 'scope has a fairly long persistence phosphor, or is a
DSO or you have been skimping on your vitamin A. 300 RPM is only 5
revolutions per second, after all.
At one time there was a rather nice disk alignemtn device for PCs. It
wouldn't allas work wit ha 1541, but it worked with most standard dirves.
It consisted of a box containing a microcontroller (8048 IIRC) and am
ADC. this connected to the PC's serial port. You conencted the
drive-under-test to the PC is B: and ran the suppleid software. This
would run on _anything_ (I think the minimum spec was 256K RAM and one
serial port).
You then sleected thge drive type from a menu and it displayed an outline
oif the PCB using the IBM line drawing characters (yes, it would run on
an MDA display). It showed you where to connect half-a-dozen wirtes from
the inteface box to the drive PCB., Then put a catseye disk i nthe drive,
select the apropraite pattern, and it displaed the catseyes on the PC
screen (again using extanded 'text' characters!) and told you how far out
of alignment is was and which way.
I've it several times, and for the drives it supports it's a lot easier
than usign a 'scope.. I think it was called soemthing like 'Microtest',
the proble, of course, is finding it.
-tony