Reusing EPROM's

[pentium]

Recently I tore a whole bunch of Z80 cpu's and 256k windowed EPROM's out of some register terminals and I have a question.
After you blank the EPROM chips, can you just plug them into a programmer and use them again?

[linuxguru]

Re: Reusing EPROM's

Yes, but you'll need a UV eraser to erase them. You can't erase them electrically.

[kc8adu]

Re: Reusing EPROM's

yes.
look for a germicidal lamp.
its a clear fluorescent tube.find one sized to fit a fixture you alredy have.
i use a 15w 18" in an aquarium hood.
careful though as they will destroy your eyes if you look at it without some sort of glasses.

[pentium]

Re: Reusing EPROM's

Will the lamp out of a UV pond sterilizer cut it?

[kc8adu]

Re: Reusing EPROM's

yes.
thats what mine was for.
i think its a g15t8

[pentium]

Re: Reusing EPROM's

Now they are blank, how do you reprogram them?

[starfury1]

Re: Reusing EPROM's

you will need a eprom burner of some type
One I used to have was for a PC AT....you will then of course need software

There some stand alone jobs and you may find constructional projects for them on the net.

you will have to check the details on the eproms you are using as some had different voltages and possibly (if memory serves pinouts slightly different).
(some pins I think had double functions)

Really depends on who made it I suppose are they like 27C256 ?
At the 256K level they may be a bit more standard ...dont know, but the old 16/32K were a bit of a mixed bag.

So yeah a Eprom burner that supports what you got is what you need, they will probably be a garden variety.
I would chase up the specs on them to be sure thought

you got me thinking back 20+ years now....

HTH

Cheers

[starfury1]

Re: Reusing EPROM's

BTW don't over cook them

[pentium]

Re: Reusing EPROM's

Really depends on who made it I suppose are they like 27C256 ?

Yep, they are the 27C256 variety.

[Maxxarcade]

Re: Reusing EPROM's

I've got an EETools RomMax that is designed for use with PC's up to 166Mhz (Needs an ISA slot). I used to use it for programming BIOS chips back when they were socketed, but it has been sitting around for years now

I'll see about posting a pic of it when I get home. I'd let it go pretty cheap if someone can use it. Only problem is you need an old DOS computer cause it won't work in Windows.

[Maxxarcade]

Re: Reusing EPROM's

Here's a rom programmer. This is just a little one, they get much bigger and more expensive. Up to ~$10k or so for a full featured setup that can program anything under the sun.

Newer ones are USB, or at least paralell port. This one uses a dedicated control card and can only program up to 8 meg 32 pin chips.

[pentium]

Re: Reusing EPROM's

That's just like what I want.
Quick connect AND isa-based interface.
You must of paid a pretty penny.

[starfury1]

Re: Reusing EPROM's

I meant to get back to this post earlier

Yeah Maxx thats the type of thing I had....it was dos based.

Think pentium probably has an old box that could handle it

heres one I found on the net
eprom programmer

this should give you an insight on how they work but its not a complete page on one Here
(seems there selling not giving you a constructional artical)

another page here

second page here is good for understanding what what with an eprom but I think you maybe past that level pentium site here

this is dealing with 64's and when they mention Turbo Pascal 5.5 you know its old but some info may help site here
(links seem to be dead)

Dont know how accurate, good or works well any of the above is but hope it helps

Cheers

[Maxxarcade]

Re: Reusing EPROM's

I tried to sell the RomMax a while back and couldn't get $25 for it It cost about $200 new I think.

[starfury1]

Re: Reusing EPROM's

mine was about that too

[pentium]

Re: Reusing EPROM's

would something like that also be capable of dumping the contents of an eprom/prom chip?
I have an SGI here that has buggy eprom chips. I could be able to revive the system if I could reload them with either a chip image or a copy I debugged.

[starfury1]

Re: Reusing EPROM's

yeah they should read as well as write eproms....

Thats the idea program reprogram.

good luck with it Pentium....I know I had some fun doing stuff like that

[Maxxarcade]

Re: Reusing EPROM's

Fixing/updating Eproms is what I used it for. It can save chip contents to a file, and most programmers even have a simple built in hex editor. I would have used the RomMax a lot longer if it had supported chips bigger than 8 meg.

What type of chips are you working with? If they are EPROMS, they usually will start with 27 in the part number. Such as 2716, 2764, 27256, 27010 etc.

Edit- I just remembered you said 27C256. Those will work with almost any programmer. That's another thing I liked about the RomMax, it had the ability to auto-detect most types of EPROMS. Different brands use different voltages and timings for programming.

[pentium]

Re: Reusing EPROM's

Oh so you can dump the contents of a chip from one of these?

[starfury1]

Re: Reusing EPROM's

yep read it, save as a file and work on it the dump it back.
mind you its usually a saved hex file
So whatever software you use would have to be able to disassemble this.
In the old days you would use, say assembler to write the program then compile it to the hex code file for burning.

I am guessing if you are wanting to edit BIOS chips you are really going to need the the manufacturers software for this.

Unless you know what hex bits at what addresses to change there is not much you can do with the hex editor.

suppose it really depend on what you working on and how you are going to use it.

If you just want to do a straight copy and save the file as a backup
no worries with that