Products > Test Equipment
Test Equipment Anonymous (TEA) group therapy thread
Vince:
COMPONENT SORTING
OK so as I said I am starting to sort my IC's now. Yesterday I started with the easiest part : the stock of logic chips old man gave me 20 years ago, that he rescued from his work before he retired.
I have never touched them. Still in their original plastic boxes with student-made labels and DIY hot glued cardboard dividers . Only difference is that they have now collected 20+ years of dust, which is really stubborn. I spent about 5 seconds on each and every chip with an ESD Brush to remove as much as I could, and 20 seconds on each plastic box, but 80% of it is there to stay unfortunately. Only way to clean that would be to throw all these chips and boxes in the kitchen sink with hot water and detergent and brush, brush.... might do that one day but not today, too much work, that.
Might also "restore" all these boxes. Remove the crusty dividers, sand down the hot glue, remove the crusty labels (most of them are coming off anyway, glue didn't age well), clean the residues... bring these boxes to new condition... because these are nice standard Euro size boxes which still cost a fortune these days, I could not believe my eyes. I can't afford to mass buy them, so it's worth restoring these old ones to me. YMMV.
So I went through all these chips one by one, cleaning them, inventorying them on paper, then putting all that data into my spreadsheet, attached below.
So it's all TTL chips which I already new of course. There are only x4 CMOS 4000 series part numbers in that drawer.
So in all, about 600+ chips and 75 part numbers or so, enough to blink LEDs for the rest of my life I guess.
x500 74 LS and only x35 74 HCT.
x21 74 'S' and oh my god, no less than x39 vanilla 74 !!!
What amazed me even more is that although a few are dated 1977, fair enough, some are much more recent, dated as late as 1989 !! :wtf:
Can't believe these antiques were still made in 1989... maybe to satisfy some big customer long term availability contract/requirement or something...
Then I found some even more funky stuff. I just love component archeology. I hated history at school, but somehow when it pertains to old electronic stuff, I love it.
So look what I found :
- A SN75_452B chip. 75 not 74. Datasheet says it's based on the vanilla TTL. It's just a couple two input logic gates (of choice depending on particular part number in the series of chips), with open collector outputs. It's strange because it's completely redundant to me ? I mean there are already open collector gates in the regular TTL portfolio, so why make these special chips to being with ?! :-//
Or.. maybe, since these chips are really old (vanilla TTL not S nor LS !), at the time the open collector gates did not yet exist in the TTL list, so they made that special chip to fill the gap. Who knows. Maybe someone here does....
- AM25LS2521. 25LS series not 74LS. Made by AMD. Datasheet says it's an "equal to" operator. It compares two bytes and tells you if they are identical or not.
- A 74 'H' chip. Didn't know that one, will need to look it up.
- An 84LS chip. Yes 84 not 74. Sure knew about the 54 military prefix, but 84 no, never heard of that one. Some more Googling required again...
- I kept the best one for dessert : you know the 74LS, you know the 74HCT .... they are different things inside... but what about mixing the two and making a "HCT_LS" chip ?! Makes zero technical sense ? But I found one ! A 7410, so marked " 74 HCTLS 10 " How groovy is that ! :-DD
I know, you don't believe me, makes no sense. But you will have to believe me because I never drink nor smoke, not my stuff, so I am always alert and sharp when not sleeping...still don't believe me ? I knew you wouldn't, who would believe such ridiculous claims as a HCTLS chip...I understand you, I do. That's why I anticipated your disbelief and took a picture of that chip, below. Enjoy.
No, it's not Photoshopped, it's real... if you want I can make a video of it, because videos are much more difficult to touch up than a still picture... and would require fancy video editing S/W that certainly would not run on my 15 year old Core2Duo computer that struggles just to keep afloat with 70 Firefox tabs open.
Then I found some more chips hiding in the digital logic " training brief case ", as could be expected. No weird chips in there though.
OK so now that the easy stuff is done, I can start digging into the second drawer of IC's.... this time random tubes of IC's and also some new components bought in the recent years, but I of course long forgot what all that is. That will be much more fun as I have no idea what's in there, it's gonna be a surprise.
TERRA Operative:
--- Quote from: Vince on June 26, 2022, 01:20:51 pm ---
- An 84LS chip. Yes 84 not 74. Sure knew about the 54 military prefix, but 84 no, never heard of that one. Some more Googling required again...
--- End quote ---
Interesting. I know of the 64xx series that were a Texas Instruments Industrial Grade (−40 °C to +85 °C) that sat in between the standard 74xx and the milspec 54xx. It was only around for a short while.
Sometimes you'll find earlier versions of TTL logic that would have different numbers depending on the manufacturer before it was all standardised to 74 and 54 prefixes.
[EDIT] It seems that 84xx was also used for Industrial Grade parts in Europe. (−25 °C to +85 °C)
mansaxel:
--- Quote from: Vince on June 26, 2022, 12:30:41 pm ---
--- Quote from: med6753 on June 26, 2022, 12:09:44 pm ---I guess I've been lucky. No issues with them at all. But given that I'm not going to touch any of them during final calibration unless I have no choice.
--- End quote ---
Yes, don't touch any of them, don't even BREATH too close to them ! When I opened the scope, all those trimmers look fine at first, it's only when I tried to operate them, barely touching them with my finger tip, that the knobs started to all off one after the other ! Sometimes just moving the scope the bench was enough to make them self destruct ! :scared:
Luckily you are in the US so you can have all of them for cheap, and fast, from Mouser like I did 5 years ago.
So it's not as big a deal for you as it was for me at the time.
--- End quote ---
As we've written time and time again, Mouser is probably the best deal there is, as long as you can stockpile needs to exceed the free shipping threshold of 50€ ex VAT. None of the others with similar stock levels even comes close to that deal.
Having said that, TME and Distrelec still get my business from time to time, and in Sweden there's a small dealer, Electrokit, that I try to use now and then, to keep them in business. If they stock the part, they're the fastest option available, and sometimes that's important.
An observation: If TME cut down on the paperwork (it's tons of forms, pro formas, invoices, et c, all printed on the best Warsaw Pact toilet paper), they'd be really dangerous competition to anyone. They'd also be able to make lots more money...
med6753:
Since 30 Oct 2015 I have ordered from Mouser 102 times. I don't even want to add up the total cost. :o :o :scared: ;D
capt bullshot:
--- Quote from: Vince on June 26, 2022, 01:20:51 pm ---
--- End quote ---
Someone had a similar experience before: https://www.eevblog.com/forum/projects/74hctls-logic/msg768989/#msg768989
Apparently they were brothers and sisters to the AHC / AHCT series:
http://www.bitsavers.org/components/samsung/1990_Samsung_AHCT_HCTLS_Data_Book.pdf
There's quite a lot of these logic series (typically) two or three letter designators, and some of them are long forgotten. Some modern ones are quite versatile in terms of level conversion capabilities and voltage domain decoupling (as in VHC, LVX, ...)
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