Re: Why can't 27C64 replace a 2764?

["Robert J. Stevens" <atreborz@execpc.com>]

"Robert J. Stevens" wrote:

> Glenn Jones wrote:
>
> > I am trying to read a 27C64 EPROM chip with my old apple 2 eprom programmer.
> > It supports and reads 2764's fine but won't seem to read a 27C64. The pinouts
> > are the same and both require 5v to read ...
> > Any thoughts?
> > Glenn
>
> I am trying to read both 2764's and a 2716. I built a breadboard Reader and was
> able to read out a AM27S19DC 32x8 Prom.
> But using the same technique I can't get the 2716 to read it seems to be all FF's.
>
> Only got one so can't check with another chip.
> I am going to stretch the wires to use a 2764 which I have a bunch.
> [Old ones given to me by a friend so they might be programmed]
> I see a 27c512 in the box and some 27128's
> I have a Pro-Log M980 with a Personality Module 9080.
> It accepts both 24 pin and 28 Pin Proms but I'm not sure what Chips it will read
> and program.
> If I can read a 2764 on my B/B then I may try to see if I can get the PRo to read
> them.
> If I measure the Pinouts I may be able to determine what Pins are Addresses and
> what pins are Data
> I am receiving and Old Apple ][ Prom Burner so that may help
> Any Thoughts
> Bob in Wisconsin

I was able to read some of my 128 and 512 EPROMS. some came up all FF's and the
others show low's .50 approx volts on all data lines.
Got a Eraser Coming so will see if erasing restores to all FF's
Gotta try the Pro-Log next