Please need help about 2708 eprom...

[James Sweet]

This doesn't make any sense. Are you _specifying_ a PROM, or are you
stuck with the ones you have on hand?

Otherwise, why would you want to buy such an old clunker of a chip?

School assignment? >:->

Thanks,
Rich

He's obviously repairing some piece of old equipment.

 

[Dirk Bruere at NeoPax]

I think Needham's used to make a reasonably priced programmer. You can
probably find one on eBay if you watch for a while.

I've got an old one (Needham).
Where does it have to go to?

 

[James Sweet]

I would bet he's working on an arcade video game system. They used this
eprom as what was called the "personality module" back in the day!

I've never heard them called personality modules, just logic boards,
game boards, etc. Most classic games were designed on a hardware
platform unique to that game, and only a few very early ones used
something as old as the 2708. By the the time the arcade boom came
along, 2716s, 2732s, and 2764s were dominant. I've got a whole basement
full of them and have been repairing them for years so I'm pretty
familiar with the hardware.

Lots of assorted equipment made in the early to mid 70s used eproms
though. Plenty of early mini and microcomputers.

 

[JosephKK]

Can't you just cobble up an adapter to treat your 2708 as if it were a
larger memory device.
So what if the high read addresses come us as "00" or "FF" Hex.
Just edit it with a text editor. Or am I missing something here?

-mpm

That is one of the few things that will not work, the -5V supply is
required. But then, a widget to make a 2708 look like a broken
2716 is possible.

 

[James Sweet]

Early Zaccaria pinball machines used five of the 2708 chips and a
reference to SOL 20 microcomputer "personality module", in which the
2708 is used can be found here http://www.sol20.org/manuals/sect-iv.pdf.

Pinball machines are a different animal, I haven't spent much time
working on them, and my only experience is with earlier
electromechanical and more recent solid state, never any of the early
solid state.

 

[JA]

of them actually boot into monitors stored on 2708s. Not willing to sell,
but if you are in the Washington, DC area, I would be happy to dump and/or
program some for you. email me if interested.

Bill Sudbrink

Thank you bill! But i'm located in europe!! You're a nice friend!

 

[Southerner]

hi guys!
I need to have an obsolete 2708 eprom programmer-reader..
It's very difficult to find modern eprom programmers that do this!
I have buyed a willeim but it does everithing but 2708!!
Well if it's possible i would make one.
I'm very good skinned as electronic handy man , but i can't know how to make
it.
Can someone help me?
And if someone got an old eprom programmer let me know!

The old Needhams PB10 programmer will work but requires an ISA slot on
the computer so newer computers can not be used for the PB10. I ran
into a similar situation but was trying to read and program 1702A
eproms. I ended up getting a Data I/O model 29B programmer (think the
model 22 will work too) on ebay. The programmers were cheap but if
getting them on ebay buyer beware. Anyway the Data I/O 29 and 22's
will read and program the 2708 and others provided that you have the
correct personality module. My 29B has the Unipack which has sevaral
different sockets that allow me to read various chips. You have to
set up the programmer for the chip you are reading and then put it in
the correct socket. If your computer has a serial port then you can
upload the hex file for the chip that you just read to your computer
and program other chips. If that is not an option then you might read
the 2708 then program a newer chip (like a 2716) and then read that on
a programmer that does talk to your computer as 2716 programmers were
very popular as DIY projects in the late 70's and through the 80's and
most programmers read the 2716 and up.

I hope that helps.