Re: Need Assistance: Apple IIc and Laser-128

[oaaland@aol.com (O Aaland)]

>From: "Gary Sutton" <otter@oz.net>


>I am having some troubles with both an Apple IIc and a Laser-128 which 
>I adopted on my thrift runs.

>The IIc just won't boot from the internal drive.  When she powers up, 
>the drive just spins.  Control-Reset drops me to the Applesoft prompt 
>as normal.  (And yes, I tried it with a system disk in the drive).

>I tried adjusting the drive speed, but that didn't help, and I tried 
>disconnecting the internal drive and booting from two different 
>external drives, both 3.5".  One is a Laser-128 drive, the other is a 
>Unidisk.  She choked on the Unidisk (wouldn't even bring up the boot 
>screen), and the Laser drive simply wouldn't do anything.  I know the 
>Laser drive works because I have used it on the IIGS.  So would the 
>problem be with the internal drive itself or the drive controller?  If 
>so, anyone know what specific component(s) might need replacing? .....
>


Two things I have found with IIc computers with a non-working drive 
is either a bad RAM chip or the IWM chip. The first step is to do a self 
test to show up any RAM problems. Hold down the SOLID APPLE (option)
key while turning on the power switch. If the ROM is new enough it will
run a test and either come up with an error code of the message SYSTEM
OK. If nothing happens in a couple of minutes then you have the original
ROM and will not be able to use the UniDisk 3.5 drive. I do not think that
the Laser drive is compatable with the IIc, some one else I'm sure knows
more about that. If you get the message SYSTEM OK then there is a very 
good chancw that the IWM chip has failed, a common problem if some-
one connects or removes an external drive with the power turned on. The 
solution here is if you are willing to do the repairs to optain a chip from
someplace loke Alltech Electronics or from an early MAC. That same chip 
is found in them at least up through the MAC Plus.

If you cannot do a self test on the machine it is possible to upgrade the
ROM to the newer version by swapping the ROM chip and cutting one 
trace on the motherboard and connecting another one.

Owen Aaland