CompuPro floppy controller differences - test-drb@ccmp.vtda.org

21 Sep 2006

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Subject: Re: CompuPro floppy controller differences
   From: ard at p850ug1.demon.co.uk (Tony Duell)
   Date: Thu, 21 Sep 2006 22:28:09 +0100 (BST)
     To: cctalk at classiccmp.org

  Oh,
I'd be happy to change the pulleys and reset the belt tensions. The 
problem is _getting_ the pulleys. Do you want to be the chap who phones 
Seagate and says 'Hello, I think you used to be Shugart, do you have the 
60Hz conversion kits for the SA801, SA851 and SA4000 in stock'  
 Pft!  If you brought them here you'd find spares from used drives or even 
 working domestic versions.  Non of those floppies are exactly rare and even
 the SA4000 is still around. 
Are they really that common in the States? They are not at all common in 
the UK any more, so don't think of that as being a source for 50Hz pulleys... 
If you were her than 50hz pulleys are a non issue. ;)

...
 And those were the easy drives. I guess RK05s
wouldn't be too hard to 
find 60Hz pulleys for either. What about RX01s/02s? Do RK07s need 
converting? RL's I know don't. But my ASR33 would. And all my audio tape 
recorders (some of which may never have had 60Hz varients).  
Lifes rough.  The solution I used once for a 50hz and later a 400hz motor
was a simple transformer output pushpull amp fed with a wein bridge osc,
a very good way to generate variable frequency sinewavs in the <100W class.
so happens I had a 12.6V CT (12A) transformer with the requisite 120V 
primary. Into a lamp load it was under 1% THD and voltage stability was
as good (5%). I ended up using it for all sorts of AC motor control 
solutions. Didn't require special parts or machine shop either.

...
 Don't worry, I am not going to move to the States.
It would be totally 
impractical for a lot of other reasons. 
Whats practicality got to do with anything?  :)

Allison