GM 2732 won't program

[Ludis Langens]

Has anyone had problems programming GM 2732 EPROMs?  I tried to make
some minor changes to the EPROM of a 1992 305 TBI.  The EPROM erased
fine, but my programmer can't write to it.  After several tries, one
byte programmed:  The byte that should have gone to 0x000 ended up at
0x800.  I ended up using a 2732A that I had lying around.

I tried programming voltages of both 21 and 25 volts.  Might the chip in
question need 12.5?  My programmer doesn't support reading out the chip
manufacturer code.  So I can't check the exact programming needed by
this chip.  This GM EPROM probably was made by NatSemi.

Incidentally, I have an old 2732B that I've never been able to program
either.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/