M27C64/64A EPROMs

[rslots]

Anyone have any M27C64/64A EPROMS that have 100 ns or better access time?  I will consider chips with 120 ns access time as well since I have good luck with them so far.  Needed for S2000 machines. Don't want anything that came from China.

[Trisail]

Good luck. These are not manufactured anymore. Anything you get from US or any where else are going to be pulls. Used chips. You might be able to get some NOS (new old stock) but then again.

Basically if they erase and program - they work.

I will admit some of the chips I order and receive do not work - but I expect that as they are used - pulls.  You usually know if they are no good right away - either they won't read on the programmer (errors), they won't erase after a couple of tries, or they erase, blank check but won't program.

[lookes]

I bought 50 chinese ones. Every one I tried erased, programmed, and verified. None worked on an S2000 board. Pretty sure the 100ns rating was a lie. Typical chinese crap.

[rslots]

I have had similar experience with Chinese chips of various types. They erase, read and program fine but do not work in the actual application. And unlike other chips if you bend a leg it easily breaks off while quality made chips will bend back and still be useable. I am ok with used chips. Have had good luck with those.

[RB]

You can use 128, 256 or 512 chips in a S2000 without offset. If you use them in a S plus you must fill the chip. 512s are easy to find 120ns or faster. I especially like these. Yes, they are from China but electronically erasable and so far have not had a bad one.

https://www.ebay.com/itm/193469147554?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

[Tilt]

 

I really like the 512k Winbond EEPROMs.  I haven't had any problems with them either and they have a fast 45ns access time.

[rslots]

Thanks. I have plenty of 512s so will go that route.