Replacing a PAL chip in an AT&T 6300

[BLCARR01 at ULKYVX.BITNET]

     I need to obtain a replacement for one of the PAL chips on my PC6300
motherboard.  The chip is located at position 6E on the motherboard which is
immediately adjacent to the two ROM BIOS chips.  It has a label of PL54 (or
maybe PL74--I can't tell for sure which one it is). According to my copy of
SAM'S COMPUTERFACTS for the AT&T PC6300 the chip is a fairly standard one with
a part number of PAL12L10CNS and should be easily programmed with a PROM
programmer provided that I had another chip from which to make a new copy.

     I have called AT&T's Technical Support number at 1-800-922-0354 many
times trying to find someone who can give me the COMCODE number for this
particular chip, but all I can get from them is that I have to talk to an
engineer at the rate of $120/hour usable in quarter-hour increments.  I did
let them sell me a ROM BIOS 1.43 upgrade (I already have 1.43) because they
told me that there was a PAL chip included with the two ROM BIOS chips.
They wouldn't tell me which PAL chip it was but I went ahead and ordered it
anyway hoping for the best, alas it was a PL90 chip located at position 2P.

     I have called AT&T's ComCode Hotline number at 1-800-654-5832, but they
weren't able to give me a comcode number for the chip that I need.  They did
give me, however, the phone number of a nearby AT&T Service Center to call
which I did. The Service Center told me to call 1-800-922-0354 and not to
bother them.

     Why do I need a replacement for this chip?  I am trying to install a high
density floppy disk with a floppy disk controller card that is advertised to
work with existing floppy disk controllers but apparently doesn't.  It is
possible to disable the motherboard floppy disk controller chip by removing one
of the pins on the chip at location 6E.  Pin 17 carries the control signal for
the FDC765 floppy disk controller on the motherboard.  I had pulled this chip
from its socket and inserted it into a socket that I made with pin 17 removed
and then placed the assembly with the untampered PAL chip back into the
original socket, except that I inadvertently put it in backwards.  When I
turned on the power the chip got fried--I'm afraid that it is no longer usable
and that some other PROM chips may have been damaged, too.

     If you have a suggestion that could help me find a replacement for this
chip I would be most happy if you would send it to me.  My return mail address
is given below.

     Thank you very much.

     Brent Carruth
     Dept of Eng Math and Comp Sci
     Univ of Louisville
     Louisville, KY

BLCARR01 at ULKYVX.BITNET