Subject: Re: fried disk][ controller - any hope ?
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From: Rubywand <rubywand@swbell.net>
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Date: Thu, 28 Jan 1999 19:47:29 -0600
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Ronny Svedman writes ...
> 
 ....
 
> I would like to know if anyone knows whats the most probable cause for
> the following behaviour of Apple disk][ interfaces:
> 
> **  one card, whips dating spring 1982 (came with the ][e) reads &
> wirtes disks just fine, but it never stops the drivemotors spinning.
> When I boot Dos3.3 in drive 1, the light stays on, and the disk spins
> perpetually. Then, if i access drive 2 on the card, it stops drive 1,
> and starts drive 2, (and reads&wirtes just fine), and thene never turns
> drive 2 off. What could cause this, and can it be fixed ?
>

     A good candidate is the 74LS132. The 556 is a fair possibility.


> ** the other "problem" card simply doesnt spin up the drives at all. i t
> doenst prevent booting the computer; i can reset it into basic, but it
> doenst spin the drives..  this one is a really old one (13 sectors,
> judging from the IC numbers

 ....

     Whichever IC connects to the /Enable lines (pin 14 on each drive
connector) is a good suspect. (On the other card, the IC is a 74LS132.) 
The 556 and 74LS05 and 9334 (or whatever IC's seem to have the same
functions on this card) are other suspects.

     For old boards like the ones above, be sure to try pulling and
re-socketing IC's.



Rubywand