DATA I/O 21A

Hello all, really trying my luck here: does anybody have a DATA I/O 21A (E)EPROM programmer and can help me with some tests to understand if mine is working well? It appear to program most common EPROMs just fine but failed on the uncommon MCM68764 which I believe is good instead (but I have only one...). Sure, the MCM is a 1980 vintage, but it was NOS. Anyone? Thanks Frank IZ8DWF

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frank
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I confirmed it is more likely a bug into the programming algorithm for the MCM68764/68766 EPROMs. If I interrupt the programming after the first pass, the EPROM appears to be programmed just fine. Otherwise it makes 20 programming passes from 0 to 1FFF and throws some error. The datasheet for these EPROMs just suggests a simple 1ms write pulse for every address and retry on the same address if not read correctly, so I'm not sure why this programmer should redo all addresses from start for 20 times before giving up. It might be an hardware fault but so far the programmer worked fine on all the 27xxx EPROMs. Also it reads fine the memory and can correctly test for blank of course. I'll try some more exotic models like the 2532 soon.

I guess it's not so widespread by now.

Thanks Frank IZ8DWF

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frank

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