WANTED: Old DIP-28 EPROM Chips

[Halcyon]

Hi guys,

As you may or may not be aware, rebuilding vintage computers is a huge hobby of mine and I've recently been helping a few mates out with similar projects. I've got all sorts of cards, cables and parts that I've collected over the years. Some I've kept for myself and others I've given away to those who appreciate vintage technology.

I've recently helped a friend out with burning some ROMs for his Acorn computers he has and am running really low on old windowed (UV erasable) EPROMs. If anyone has any they can part with (I'm happy to pay), especially for any M27C128 types, it would be greatly appreciated!

[dexters_lab]

just checked and i don't have any 27c128, all most of mine are c256 or c512

i'll check with someone i know, they did have some NOS tubes of eproms but i don't recall exactly what they were

[wraper]

You can get M27C128 on ebay. However many of them had some Chinese magic applied to them. Old marking removed and new one applied. So if silicon die looks the same, it's the same IC, however don't count on date code and speed grade.

[ebclr]

Isn't exactly what you looking for but, is what will solve your problem

http://ww1.microchip.com/downloads/en/DeviceDoc/20005022C.pdf


If you wanna the old stuff

https://s.taobao.com/search?q=M27C128&type=p&tmhkh5=&spm=a21wu.241046-global.a2227oh.d100&from=sea_1_searchbutton&catId=100

[perieanuo]

Hi guys,

As you may or may not be aware, rebuilding vintage computers is a huge hobby of mine and I've recently been helping a few mates out with similar projects. I've got all sorts of cards, cables and parts that I've collected over the years. Some I've kept for myself and others I've given away to those who appreciate vintage technology.

I've recently helped a friend out with burning some ROMs for his Acorn computers he has and am running really low on old windowed (UV erasable) EPROMs. If anyone has any they can part with (I'm happy to pay), especially for any M27C128 types, it would be greatly appreciated!

Where do you live?

Envoyé de mon HUAWEI NXT-L29 en utilisant Tapatalk

[legacy]

all most of mine are c256 or c512

as mine, plus a lot of C010, and a couple of C020 
(which is the biggest UV_ROM I have, LOL)

[macboy]

I came across http://www.epromman.com/ the other day, on a retro arcade game forum. Worth a try.

[guido]

I'll be going to a clearance sale of electronic components in december or january. Three rooms which were filled to the roof with equipment and components, which we have been plundering for the last years. So all the good stuff hast mostly gone, allthough you can still find new gems under all of the remaining stuff. There will be one last clearance sale, where prices will be even lower than usual. After that it's gone.

One of the thing you find everywhere are eproms. Many of them, really really MANY of them. I have collected all of the non standard EPROMs for my own repairs. But 27128 i consider bog standard    I think there are plenty of them around at the site. Sent me a PM and i will see what i can do. Shipment would be the cost driver.

I have Acorn Atom machines myself.

[Halcyon]

You can get M27C128 on ebay. However many of them had some Chinese magic applied to them. Old marking removed and new one applied. So if silicon die looks the same, it's the same IC, however don't count on date code and speed grade.

Yes I know, I'd rather avoid anything that might have been 'tampered' with and go for collections sitting in EE's workshops somewhere.

Where do you live?

Sydney, Australia.

I came across http://www.epromman.com/ the other day, on a retro arcade game forum. Worth a try.

Thanks, looks quite reasonable.

[Kilo Tango]

You could probably use a 27256 in place of a 27128. Only difference is 27128 has /pgm on p27, /ce on 20, /oe on 22. 27256 has /ce & /pgm on 20 and 27 is now A14. Once programmed it would probably work, just not addressing the upper half of the chip. The whole family of eproms were basically socket compatable.

Ken

[SeanB]

Correct on the common family pinout, many old boards had a jumper so you could put a 24 pin device in, when you had firmware below 64k in size and thus could use any 2764 or greater size, whichever was cheaper.  Many boards also had select jumpers as the developers also wanted to have the flexibility to use cheaper larger size proms as they got cheaper. I have seen many where, as the size stayed the same, the actual chip inside the window shrank, so you get a 27128 at the early stage filling the entire large window, but later generation ones with lower program voltages being a very much smaller die. That is why you get ID strings inside many modern proms, so the programmer can set up accordingly to use the right algorithm ( aside from the voltage being correct and then 50ms per byte as default) for fast programming.

[perieanuo]

Quote from: perieanuo on November 03, 2017, 10:48:21 PM

    Where do you live?


Sydney, Australia.

Nice!In this case it isn't worth to send you some eeproms, even at 1 euro/piece, I think you get them cheaper on ebay.
I'm from France.Worst, my godfather lives in Sydney but I lost contact...
Regards,
Pierre

[FrankBuss]

Recently I used an AT27C256 for a DIY Vectrex cartridge:



They are really cheap: https://www.digikey.de/short/qtwm1d Only one time programmable, can't be UV erased, but doesn't matter much for this price and you can emulate most old computer systems anyway on a PC before burning the ROM. My TL866 could burn it with no problems in seconds. The pinout is nearly the same as for the 27C128 EPROMs, you might only need to tie A14 to GND, or VCC, if you burn the content in the upper half or copy it.

[IconicPCB]

I thought i had some in th bottom of the junk bin.
Turns out they are d8748 micros.

[Sjokolade]

Found these at the dump some time ago, useful for anyone here ?

[hermit]

I have some M27C256B.  Still in the tube the came in originally.  Let me know if you don't find something better.

[SeanB]

I have a number of SEEQ eproms as well, will have ot check if the TL866 can program them, and if they still work after 30 years of storage.

[max-bit]

for sale these ICs?

[carlstechshed]

I've got two tubes (24 ICs total) of AMD 27C128 EEPROMs.

Date codes range from 1995-1998. They are all new-old-stock from an electronics company I cleared out.

Let me know if you're interested