Re: Drive Keeps Running...

[oaaland@aol.com (O Aaland)]

Tony Cianfaglione writes:

>
>   I have a IIc which boots fine, displays all pixels (no missing dots),
>runs full 80 columns, will do a cat on ProDOS and a CATALOG on DOS 3.3,
>will load and run Apple II Desktop, will load and run all of my 8 bit
>games and programs and generally works well.
>
>   The disk drive just won't stop running.  I have to use a Control-Reset
>to stop it at each interval when I want to remove a disk.  It will allow
>me to enter any commands I want at any time but the drive keeps on running
>(much like the Energizer Bunny).
>
>   Plugging an external drive in the back causes the external drive to
>keep running while the built-in drive stops so it is obviously passing the
>problem along out the Smartport to the external drive.  Everything else
>runs and works fine.
>

When I have encountered this problem the solution has been to replace the 
IWM chip. This is the controler chip for the disk drives. If an external 
drive is connected or disconnected while power is on this chip can blow.
The part number on the chip is 344-0041-A. It is located under the inside
rear corner of the disk drive. Parts source, either Altec or an old Mac
motherboard. I believe all macs up through the Mac Plus used this chip. 
It is also found on the UniDisk 3.5 Disk Controler Card.