how to decipher codes printed on EPROMs? hello, i have a few EPROMs in my console cartridges, which manufacturing date could be easily deciphered (for example, 8223 stands for 23rd week og 1982). but some other EPROMs aren't this clear. I often come across Hitachi 27xx EPROMs like the HN462732G, with manufacturing date marked as: 2F3 RD or 2E3 R. how to decipher those codes? 2 might stand for 1982. But what for F3 RD and E3 R? i searched over the internet, and found no information on this matter. :-( thanks in advance for your replies.
I tried Hex, but no succes, I did found a datasheet and it apears to be from a larger book, maybe a description on how to read this code is somewhere inside. I can try ask a friend of mine if he know some tricks but I dont know I he has ever worked with Hitachi eproms (and/or has a book about it.) Good luck
2F3 = 3rd week, June, 1972 2E3 = 3rd week, May, 1972 Google "japanese ic date codes" for great victory
Considering Space Invaders didn't come out until 1978, that seems like a very old chip to be using in production, if that code is correct.
i cant believe the eprom was manufactured in 1972.... the game written on those EPROM is from 1982, as well as most of the EPROM's I have here at my place - they're games for the Creativision console, released in 1981. i assume the "2" stands for 1982. thanks much for the precious information!
All the references I could fine for date code format all state 197x. However, I just found a old ass usenet message that states 80s may have used the same format and you have to guess the decade based on the font.. I guess, you should look to figure how when those chips started (and finished) production, when the complete item came out, etc to guess the decade.
The EPROM was invented in 1971, if it was really a 1972 I would expect it to look like this: http://en.wikipedia.org/wiki/File:Eprom.jpg That was the typical early 70's IC packaging, especially for RAM, ROM, and Processor chips.
Another good point. So that suggests 80's - as 90's would be too late. This is what the usenet post seemed to suggest too - basically you can guess the decade easily enough.
I actually collect vintage ICs so I thought that info would be relevant to this discussion, brown ceramic started becoming common around 1976-78.
Yeah, 80s sounds more feasible to me. I'm a little confused as to what exactly we're dealing with here as the OP was a bit vague. Whilst it's in the arcade section so I'm assuming an arcade board, the OP did mention console cartridges. Surely there aren't many retail carts with EPROMs, so maybe that was just a translation error? Lol, I remember that thing about the font! Basically ascertain for yourself whether it looks like a 70s chip or an 80s chip. Perhaps we are missing some information on the correct way to decode this. I'll have to dig out my old data books and see what comes up.
I want a proto repro with White caramic eproms now maybe put a X360 nand on a white woth gold chip anyway, good point are being made here, earliest chip at my home are then from the 80s and up.
