[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
IIc : Drive-controller IC?
sebugg@presby.edu Sept. 30, 1993
WHICH IC CONTROLS THE DISK DRIVE ON THE "ORIGINAL" IIC"?
========================================================
I have two "Unidisk 3.5" Apple IIc computers, both of which work fine.
Recently I bought a broken IIc in as-is condition. The IIc arrived today
in better condition than expected for its $25 purchase price. The external power supply
works great, the casing is percet, and the internal disk drive (when tested
on another computer) works fine.
It is the "original IIc," the older 1984 model, with white casing, and no
internal self-test at power-up.
It has just one fault: It wont read the disk. I connected another disk
drive that is known to work, and it could not read that one either.
Thus the fault is in the motherboard, not in the disk drive. When I
power up with a disk in the drive, the error message CHECK DISK DRIVE
appears on the screen. The drive starts and spins, but does not sound like
it is picking up the tracks; it spins blindly. Thered lamp, DISK USE,
comes on and stays on during the spinning.
The computer looks so clean and its fault is so specific that I wish
to attempt to repair it, rather than to cannibalize it for spare parts.
I have successfully desoldered and replaced one of the RAM chips on another
IIc, so I feel that I am competent to do motherboard surgery to fix this IIc.
What I need is detailed advice regarding which ICs are most likely to have
failed. Only the four largest ICs are socketed; all others are soldered
in place.
Can anyone advise me? Which IC is most likely to have failed?
888888888888888888888888888888888888888888888888888888888888888888888888888
88 Stephen Buggie Psych Dept Presbyterian College Clinton SC 29325 88
88 sebugg@presby.edu voice: (803) 833-8337 or 833-1632 88
88 IIe/IIc loyalist 88
888888888888888888888888888888888888888888888888888888888888888888888888888