Please need help about 2708 eprom...

Yes , that's the point, i don't wanna to modify all my equipement!

Reply to
JA
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On a sunny day (Thu, 05 Jun 2008 19:00:46 GMT) it happened "JA" wrote in :

Would it not be a lot cheaper to make a little plug in board with for example a

2716? These once existed with SRAM and battery too IIRC. Depends on how many EPROMS of that pre-historic age you need to replace.
Reply to
Jan Panteltje

The differences between the 2708 EPROM and the next device in the series:

2708 2716 +----\\/----+ ---+ 1 |A7 24| VCC | VCC 2 |A6 23| A8 | A8 3 |A5 22| A9 | A9 4 |A4 21| VBB | VPP (-5V on 2708) 5 |A3 20| WE/CS | /OE 6 |A2 19| VDD | A10 (-12V on 2708) 7 |A1 18| VPP | /CE 8 |A0 17| D7 | D7 9 |D0 16| D6 | D6 10 |D1 15| D5 | D5 11 |D2 14| D4 | D4 12 |GND 13| D3 | D3 +----------+ ---+

ASCII pinouts from:

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2708 2716 +--------\\/--------+ +--------------+ 1 -|a7 vcc|- 24 A7 |1 +--+ 24| VCC 2 -|a6 a8|- 23 A6 |2 23| A8 3 -|a5 a9|- 22 A5 |3 22| A9 4 -|a4 vbb|- 21 A4 |4 21| VPP 5 -|a3 we/cs|- 20 A3 |5 20| /OE 6 -|a2 2708 vdd|- 19 A2 |6 19| A10 7 -|a1 program|- 18 A1 |7 2716 18| /CE 8 -|a0 o7|- 17 A0 |8 17| D7 9 -|o0 o6|- 16 D0 |9 16| D6 10 -|o1 o5|- 15 D1 |10 15| D5 11 -|o2 o4|- 14 D2 |11 14| D4 12 -|gnd o3|- 13 GND |12 13| D3 +------------------+ +--------------+
Reply to
JeffM

Are you stuck with the three-supply 2708? They're a nightmare to program, unless you have the programmer; I wouldn't recommend trying to build one.

Why not pick a 1KX8 chip that's a little more modern, like flash? I hear they're relatively easy to program; you could use a bigger one by just ignoring part of the address space.

Tood Luck! Rich

Reply to
Rich Grise

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

Reply to
Rich Grise

He's obviously repairing some piece of old equipment.

Reply to
James Sweet

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

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Dirk

http://www.transcendence.me.uk/ - Transcendence UK
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Reply to
Dirk Bruere at NeoPax

I have a BK model 840 universal E(E)PROM programmer and external "pod" where the EPROM plugs in. I have the software onmy HD which i can copy to a floppy or CD; i might have the original floppy(ies) but cannot say without looking. You will need an older computer with at least one ISA bus for the card. It is capable of programming a large number of device types made by a goodly number of makers. I have never had any trouble with it and fully expect it to be in brand-new condition, even tho i had used it a number of times. E-mail me if interested.

Reply to
Robert Baer

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!

Reply to
Stephen D. Barnes

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.

Reply to
James Sweet

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.
Reply to
JosephKK

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

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Reply to
Stephen D. Barnes

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.

Reply to
James Sweet

"Bill Sudbrink" ha scritto nel messaggio news:g298m9$q8r$ snipped-for-privacy@news.ums.edu...

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

Reply to
JA

ke

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.

Reply to
Southerner

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