Programming 2708 (1k x 8)

Richard A. Cini rcini at optonline.net
Fri Apr 14 21:05:27 CDT 2006


Eric:

	What I did was build a 2708-2716 adapter using a DIP header and a
DIP socket stacked together with the proper wiring to map the pins. Then, I
brought out a small 3-pin connector with -5, -12 and G on it, which I
powered from the EPROM card in my IMSAI. I laid my programmer on the open
mainframe, put the 2708 in the socket, put the stack in the programmer,
hooked up the power cable and set the programming software for 2716. Works
like a charm.

	By the way, the reverse can work, using a 2716 in a 2708 socket,
with the right pin mapping.

Rich

Rich Cini 
Collector of classic computers 
Build Master for the Altair32 Emulation Project 
Web site: http://highgate.comm.sfu.ca/~rcini/classiccmp/ 
/************************************************************/

-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of Eric J. Rothfus
Sent: Friday, April 14, 2006 9:57 PM
To: cctalk at classiccmp.org
Subject: Programming 2708 (1k x 8)

I was somewhat shocked to find out that my TopMax
EPROM programmer doesn't handle the vintage 2708
1k x 8 EPROM.  A very interesting little EPROM
the 2708.  It requires +5, -5, and 12v.

Anyway, any advice out there for working with
these old little beasties?  I'd like to first
read one, but eventually program them.  Or
maybe I should program the 2716 and substitute
them (with appropriate bent-up pins)?  Maybe,
too, I could read them after telling my TopMax
it is a 2716 and (again) bending up a few pins,
or maybe using a pulled-pin socket.

The 2708's are found in an S100 EPROM card
in my newly acquired Altair.

Eric




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