Re: Adjusting speed of a Disk II!

[valthoff@magnus.acs.ohio-state.edu (Victoria M Althoff)]

TO ADJUST THE SPEED OF A DISK ][
(assuming that you have a program to tell you how fast it is running)

1.  Remove the four screws from the bottom of the case.
2.  Slide the case backwards over the drive mechanism, exposing the mechanism, 
and remove the case.
3.  Locate the multi-turn potentiometer near the back of the mechanism, on the 
right-hand side (viewed from the front).  This potentiometer controls drive 
motor speed.

IF IT IS YOUR BOOT DRIVE AND IT'S SO BAD THE COMPUTER WON'T BOOT:
After removing the case, remove the four flat-head screws from the base plate.
Squeeze open the cable clamp on the back panel of the drive.  Then, remove the 
back and bottom from the drive mechanism.
Invert the mechanism and power up the computer.  To activate the drive from 
BASIC, type POKE 49385,0; otherwise, just use the boot-up routine to get it 
running.
Using a flourescent light, look carefully at the strobe disc on the bottom of 
the drive central shaft.  The markings should appear stationary.  If they 
don't, the speed is mal-adjusted; use the potentiometer described above to 
adjust.

NOTE:  Many strobe discs have two sets of markings.  Use the one that matches 
your power line frequency (60 Hz US, 50 Hz Europe).

Reassembly is the reverse of disassembly.  I can perform the entire procedure 
using only my Victorinox Swiss Army Knife Can Opener/Flat Phillips blade.

--Dave Althoff, Jr.
(Those old Disk ]['s will probably outlast the typical UniDisk 5.25!)