"Ancient" components - need datasheets? - Page 1
Forum section: electronics / beginners

author: bitman
author_rank: Unknown
timestamp: March 12, 2018, 03:18:14 am
content: I had a bit of time this weekend and went through my box of "misc components that I don't know what is" to give it a whirl. Let me start out by saying that google was of no help here. Going to the manufacturers website didn't help either. I guess if you have old data books from the 70ies these may be found - are there any other means to identify components that have "a few years" of aging behind them?There are 3 components here - one is an old LED display as we used them in calculators in the 70ies. I would really love to have a data-sheet as the pin design makes NO sense to me (reversing voltage turned a different segment on!?). Next there's what I think is an oscillator? Finally a multi-plexor of some kind but I cannot see any traces on how the pins are connected, so I'm really puzzled at this "simple" multi-plexing with a few gates (and/or).Anyway - the real question here is to figure out a better way than google to identify components like this. I've got more in the drawers so I'm looking for a way to figure out what they are - I just ran out of ideas to figure that out.

author: flynwill
author_rank: Regular Contributor
timestamp: March 12, 2018, 03:52:52 am
content: Good luck finding data sheets for any of those.The LED display shouldn't be hard to trace out by observation. It will be wired as a multiplex display. Almost certainly red LEDs. The forward current from the "diode test" setting on your multimeter should work well to suss out the arrangement.You are correct the second object is a crystal oscillator. Probably 10Mhz from the label. These virtually always have the same pinout -- Apply 5V between pin 14 and 7 (I know there's only 4 pins, but pretend it's a 14-pin dip with most of the legs cut off) and you will see 10MHz on pin 8.That last one is harder but probably could be reverse-engineered if you really want to.

author: Rog520
author_rank: Regular Contributor
timestamp: March 12, 2018, 04:23:04 am
content: The first one is a National Semiconductor NSA1166. Data sheet here:https://www.jameco.com/Jameco/Products/ProdDS/2210976NAT.pdfThe second is an Abracon oscillator. Looks like 10MHz, probably like the temp compensated version here:http://www.abracon.com/Oscillators/actx1018-acvtx1018.pdfThe third, I have no idea

author: Canis Dirus Leidy
author_rank: Regular Contributor
timestamp: March 12, 2018, 08:30:24 am
content: Quote from: Rog520 on March 12, 2018, 04:23:04 amIn the third photo... The central chip (SOIC14 with the Harris logo) is probably 74HC20, but I can not identify the two SOIC8 on the sides (they have a faint Motorola logo and "Q17 R45" marking but my google-fu is too weak).

author: bitman
author_rank: Unknown
timestamp: March 12, 2018, 01:58:02 pm
content: Quote from: Canis Dirus Leidy on March 12, 2018, 08:30:24 amThere are two HC4051http://www.onsemi.com/pub/Collateral/MC74HC4051-D.PDFon the other side. And HC32 (OR) HC20 (AND) and the two chips that have barely any print on them. Because of the two multi/demultiplexers I presume that's the main function. Each of them is 8 bit, so given the pin layout this makes no sense. And as I mentioned, I'm unable to see the traces in the PCB to see what connects to what. I'm getting the feeling this is a specialized component for a particular unit - and I'm pretty sure I won't find any use for it. My question was more about how/where can I go to search for legacy components like this to determine what it is I have.Thanks for all the input so far.

author: Rog520
author_rank: Regular Contributor
timestamp: March 12, 2018, 02:30:26 pm
content: The only thing I can ID on that module is the brand (C-MAC). Probably commissioned for an OEM so it's unlikely that data on it is publicly available.Most stuff can be tracked down on Google if it was popular at one time or another, especially if you can ID a logo, brand, country of origin, part numbering scheme....If Google turns up absolutely dry despite your best efforts then it's usually a matter of finding someone with a hard copy of the data. That's a real challenge since few people have kept their old data books, especially for really obscure stuff. Forums like this are probably the best resource.