User`s guide

6. Re-mount the daughter board. Mount the 5k Ohm pot. Install knob.
7. Bring the drive back to the computer. Slide it onto the case bottom plate,
reconnect main ribbon cable, replace bottom bolts, slide on and re-fasten case
top.
You can use Copy II Plus, XPS, APEX, or one of several other utilities to
set speed (see next question). A good starting adjustment will be near the
center of Speed Knob's range. Once speed is adjusted, you can loosen and re-set
the knob so that its position indicates a "correct" speed setting.
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003- How can I adjust my 5.25" drive for the best
performance?
The typical 5.25" drive will run for months with no need for maintenance
save an occassional dusting or session with a head-cleaner disk. When adjustment
is required, it will usually be to fine-tune Speed or, less often, to set track
centering.
If a 5.25" drive has difficuly reading diskettes, including those it
created, and head-cleaning does not help, then, the odds are it's time to adjust
speed. If your drive is a Disk ][ and does not have the external 'Speed Knob'
mod, look for a small hole on the lower right side near the back-- some owners
add this hole to allow easy access to the Speed Adjustment mini-pot screw. If
there is no hole, you will need to remove the case. (Remove bolts on bottom and
slide out the drive through the front.)
On the 5.25" Apple 'Platinum Drive', the Speed Adjustment is accessed
through a small hole on the bottom of the drive near the front on the right
side. Non-Apple 5.25" drives may place the Speed Adjustment almost anywhere.
Look for a small hole through which you can see a screw head. If you don't fine
one, remove the case and look for a mini-pot labeled "Speed" or something
similar.
The most popular speed adjustment software utility is, probably, dear old
Copy II Plus. From the menu, just select "Verify", then "Drive Speed". Put a
diskette into the drive you want to adjust and, turning the Speed Knob (or min-
pot shaft) use Copy II's numeric speed display to zero-in on the 'magic' 200ms.
number. (Standard Disk ][ rotation speed is 300 rpm, which comes out to be 0.2
seconds per revolution.)
Other speed adjustment utilities show an rpm number or a hires pointer.
Whatever, all speed check routines need to read AND write; so, you will usually
need a "scratch diskette" which you do not mind having over-written.
Track-center realignment is needed when a Disk ][ writes and reads its own
disks fine, but does not 'communicate' with many other Apple II 5.25" drives. It
generates disk errors when reading disks written by other drives and other
drives have the same problem with its diskettes.
CALL A.P.P.L.E's APTEST, now in the public domain, tests track-center
alignment. With this software, the user checks the alignment of the drive with
disks regarded as well aligned --- such as Apple diskware supplied with the
computer or some unprotected, original, commercial software diskette. (In a