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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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8th Apr 2021, 4:19 am | #1 |
Triode
Join Date: Feb 2021
Location: Los Angeles, California, USA
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National Semiconductor IC batch codes
Does anybody know how to read the batch codes or manufacturing codes on old NS integrated circuits? For instance, I have a DM7400N with a '007' on it and another one with a '037P' and another with '-827 B+'. They seem to be all over the map. Just wondering if anyone knows how to read those. Thanks.
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8th Apr 2021, 1:50 pm | #2 |
Nonode
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
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Re: National Semiconductor IC batch codes
Don't know if this helps: from a 1995 databook
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8th Apr 2021, 2:43 pm | #3 |
Heptode
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Re: National Semiconductor IC batch codes
Something does not look quite right with the font, and the date code should normally consist of four digits together with a character or two. Picture attached of a genuine Nat-Semi DM74x which was manufactured in 1985 week 52.
Edit: matches format as shown in previous post. As an afterthought, does the ink come off easily? Rich
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8th Apr 2021, 9:42 pm | #4 |
Octode
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
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Re: National Semiconductor IC batch codes
I just checked on my MK14 and the date codes are /831 on the DM74S571Ns, /845 on the INS8060N, /847 on INS8154N, /821 on DM7445N, 7845 on DM74LS178N, 839 on DM74LS157J, -833 on DM80L95N, -816 on DM7408N, -831 on DM74LS04N, -841 on DM74LS00N, -840 on DM74LS08N.
I think the variation will be from different manufacturing sources not always following the letter of the spec. |
8th Apr 2021, 9:45 pm | #5 |
Nonode
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Re: National Semiconductor IC batch codes
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9th Apr 2021, 1:35 am | #6 | |||
Triode
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Location: Los Angeles, California, USA
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Re: National Semiconductor IC batch code.
Terrific! Thank you! Though it would seem to be a different schema than the older ones like I have.
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13th Apr 2021, 2:40 am | #7 | |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
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Re: National Semiconductor IC batch codes
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13th Apr 2021, 2:42 am | #8 | |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
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Re: National Semiconductor IC batch codes
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13th Apr 2021, 3:15 am | #9 |
Moderator
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Re: National Semiconductor IC batch codes
Is it ink, or has it been writen by laser?
Is there anything written on the underside. David
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13th Apr 2021, 5:38 am | #10 |
Triode
Join Date: Feb 2021
Location: Los Angeles, California, USA
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Re: National Semiconductor IC batch codes
LOL!
Thank you. That makes total sense. Except I've seen a board I know was built in 1978 which has the same NS IC's (same logo and font) with code 027P. That would mean 1980 week 27, right? Except that's after it was put on the board. Something isn't adding up. Maybe I've finally found the glitch that proves our universe is a simulation. Thanks Maarten. |
13th Apr 2021, 4:26 pm | #11 |
Octode
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 1,298
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Re: National Semiconductor IC batch codes
Yes, my MK14 is an issue IV from end of 78 or sometime early in 79. I think there was also an issue V, though not sure when that was introduced and I don’t think there were so many of those.
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13th Apr 2021, 5:26 pm | #12 |
Triode
Join Date: Feb 2021
Location: Los Angeles, California, USA
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Re: National Semiconductor IC batch codes
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13th Apr 2021, 8:41 pm | #13 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
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Re: National Semiconductor IC batch codes
The only use of WWY I'm aware of, are Philips date codes on assemblies and equipment, up to the mid to late 1960's.
Philips later did use non-existing week numbers to indicate months and quarters, but I don't think anyone else did that either. I'd guess the 027 date code could be an IC that was replaced later on. |
13th Apr 2021, 11:34 pm | #14 |
Triode
Join Date: Feb 2021
Location: Los Angeles, California, USA
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Re: National Semiconductor IC batch codes
I would've thought the same, but this is where it gets interesting. That board was built for a prop in a movie which was released in the spring of 1980. After which, the board was never used again. To make it more certain it wasn't simply replaced, there was a duplicate backup board which was never used and it has the exact same IC on it with the same 027P.
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14th Apr 2021, 6:26 am | #15 |
Triode
Join Date: Feb 2021
Location: Los Angeles, California, USA
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Re: National Semiconductor IC batch codes
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15th Apr 2021, 1:21 am | #16 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
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Re: National Semiconductor IC batch codes
Your post #14 would have had me doubting it as well. Could have been something external that blew up this IC during usage as a prop? Then it would of course make sense that the IC on the spare board was also blown as the first action after a malfunction would have been to try the spare board.
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15th Apr 2021, 6:46 am | #17 | |
Triode
Join Date: Feb 2021
Location: Los Angeles, California, USA
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Re: National Semiconductor IC batch codes
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