Re: How to adjust the speed of floppy drives?

[mjmahon@aol.com (Michael J. Mahon)]

Tom Zuchowski wrote:

>"Ernest" <leucoplast@seanet.NOSPAM.com> wrote in message
>news:RpdQb.3643$U%5.20468@attbi_s03...
>> I have a couple of "hacked" disk ][ style drives that are no longer
>working.
>> I'm not exactly sure of what the problem is but I think that the speed
>> adjustments are off. The former owner moved the adjustment pots to the
>> front of the drive because (according to him) the drives needed to be
>> adjusted frequently and he was tired of having to take the drives out to
>> adjust them. The drives also have Write Protect toggle switches and the
>> red/green lights on the front too (also added by the former owner.) I
>don't
>> want to toss the drives out if I can repair them but I'm not sure how best
>> to do it.
>
>Apart from accessing copy-protected disks, another possibility for the need
>for convenient adjustment might be that the drive motors are wearing out.
>This has happened to me. I had a drive that simply would not stay adjusted.
>It finally got bad enough that I couldn't even adjust it any more while the
>speed program was running, as it hunted all over the place. I chanced upon
>an exact replacement for the motor in a surplus electronics catalog and
>bought a couple. After I replaced the drive motor, the drive was again
>rock-solid.

Thus demonstrating why making it easier to manually adjust
the speed is not a cure for a failing motor.  The fact that the
original owner of the drives had done it to both of them argues
that the modification was not an ill-advised adaptation to a
motor failure (which is actually pretty unusual for Apple drives,
since they run only when being accessed).

BTW, writing data with a drive that is having speed problems
is a good way to create unaccessible disks, and should be
avoided.

Speed hunting can be caused by the motor or the motor
control, or by unusually variable rotational friction, or by
a partially hardened drive belt.

Sometimes just running a drive that has been idle for a while
will limber up the drive belt sufficiently.  I've described the
technique for relieving turning friction in a "flattened" diskette
elsewhere.  But if it's the motor, then replacement is the only
real option.

At this point, cannibalization of a non-functioning drive may
be the best bet for motor replacement.

-michael

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