Newbie- Help cross referencing Eprom chips

[nlh]

Hello,

I am in the process of trying to cross reference some older Eprom's to new units if available. They are early 80's vintage Intel chips. The part number is D72128. I am guessing the 128 suffix means 128K? I'm not that familiar with Eproms and doing some searches on the net yielded no results on that part number, although I did get some hits on 27C128 from different manufacturers.

Also looking for info on HM6167LP-6 IC's. I believe these are RAM chips but don't know for sure.

Basically, I am looking to do some projects on an early 80's Mazak VQC w/ M2 control.

If anyone needs more info just let me know.

Thanks

[bharbour]

A D27128 is an NMOS EPROM holding 128K by 8 bits or 16K Bytes. A 27C128 is pin compatable in read mode, but requires different progamming algorithms and voltages.

The HM6167LP is a Hitachi 16K by 1 bit SRAM.

BobH

[nlh]

Thanks BobH,

After looking on datasheetarchive.com I was able to find pdf's on the HM6167LP-6 SRAM. However, nothing on the Eprom.

I guess my question at this point would be, is the differences between the D72128 and 27C128 in the programming end, or, due to different voltages, the latter simply wouldn't work becuase the supply voltage required would be incorrect? I would need to be able to read the data from the D72128 and then write it onto a suitable replacement.

What is a good eprom programmer on a economy budget? I see many on e-bay in the $20-$50 range. Most claim to cover all types including NMOS.

Thanks again

[bharbour]

I misread your post. I read D27128, not D72128. Are you sure it is not a D27128?

There were a bunch of different voltages in use for programming EPROMS and I would have to look up exactly what an Intel D27128 used. The CMOS versions were mostly 12V programming, and used an adaptive programming algorithm instead of the fixed pulse length that was common for the NMOS parts.

The programmer I have is an old Xeltec that runs on an ISA bus PC. The software is pretty lame, but it does work. I don't know what would be a good modern programmer.

Sorry I can't be more help,

BobH

[nlh]

Yes, you are correct, they are D27128 Intel IC's. With that number I am able to find a data sheet. No need for you to apologize, you've been a great help to me.

I've found several places to buy the 27C128 chips. Since I'll only be reading from the old Intel EPROM's I shouldn't need to worry about the difference in programming formats.

I also have a couple other chips that I will need to find replacements for. First is an MBM2764-25, the second is an MB7058(this one is very small).

BTW, Although I've dabbled in electronics and circuit repair over the years I'm very new to EPROM programming. Is there any chance of damaging the D27128 chips when attempting to read from them? Any good books out there on EPROM related subjects?

Thanks,
Nate

[bharbour]

The MBM2764-25 should be a Fujitsu 64 KBit by 8 part. There may be 27C64's available. EPROMS were pretty much a commodity part.

I am coming up empty on the MB7058. I think it might be a DRAM, they were commonly in 16 pin packages, 1 bit wide and muxing the high and low halves of the address bus. On a board, you would find them in groups of 8 or 9.

I used to have a major collection of dinosaur computer hardware that I was keeping databooks around to maintain. A couple of interstate moves and my interests drifting more toward machinery has thinned out both.

Reading EPROMs is pretty safe, just make sure that the programmer is powered up and configured for the correct part number before you plug the EPROM in. Unplug the EPROM before you turn off the programmer. Lastly, the programmers usually have a 32 pin socket that is used for all parts down to 24 pin EPROMS. Make sure that the EPROM goes into the correct part of the socket.

I don't know of any books other than the manufacturers data books. There may be some out there though.

BobH