The Ware for this month is shown below:
It’s a tiny portion of a much larger ware, but for various reasons I think this is sufficient for someone to guess at least the type of ware this came from, if not the exact make/model.
There’s a particularly interesting bit about this ware, which you can see in the center of the left module – a tiny bit of wire that is out of place! It’s pretty rare to find small manufacturing defects like this in the wild. So far, this defect hasn’t caused a functional issue but I suppose some day it may. I wonder if this is a so-called “tin whisker” (i.e., a piece of metal that will keep growing with time until it causes a fault), or if it is just an errant bit of metal left over as an artifact of the manufacturing process. Only time will tell, I suppose!
Looks like one of those cute, 4-digit 7-segment “smart” displays where the segment LEDs are cast into these transparent epoxy “bubbles” to optically magnify them.
Definitely “bubble” 7-seg LED displays. Used in calculators and the occasional wristwatch back in the 70s. The actual LED dies aren’t really visible – they’ll be between the prongs of the fork-like metal areas, one per segment. Made by a number of manufacturers (like HP – one of theirs is the HP 5082-7400).
The thing that stands out here is that the epoxy bubbles aren’t tinted red, which is a little unusual; haven’t got any like that in my collection
Separately, I heard Big Clive refer to those little unwanted strands of metal sneaking into things – especially PCBs – as “oh there’s a wee George Michael, a Careless Whisker”, and that’s stuck with me
one contact _fork_ per segment – these look like they have 4 LED dies per vertical segment, 3 per horizontal. You can just about see the dies (dices? Chips?) if you zoom in
Yes, from the construction I suspect one would see dots, not lines like most of these things. The only ones like this I can find are Litronix but I could not find something exactly like this (4 and 3).
It’s two digits of a 7-segment LED bubble display. Likely something like NSA1166 or similar. I grabbed one when a NOS lot was on sale at Jameco
I think you are right on the manufacturer side, the unique design pattern of the diode layout (inverse) and the gold plated theme strongly suggest this is a National Semiconductor bubble 7segment LED display. Base on the datasheet
https://www.datasheet.live/pdfviewer?url=https%3A%2F%2Fpdf.datasheet.live%2Ff5e95fdf%2Fnational.com%2FNSA0038.pdf
This seem to be NSA0038 or some earlier series as it only 7 segment with a DP.
I dug out my NS1166. While similar, it’s not a match.
https://mstdn.social/@adistuder/114445928905606890
Lol, I have one of these! It immediately looked familiar. I’m sure this was used in a calculator, however there is nothing to indicate a manufacturer.
https://jf-it-services.de/public/PXL_20250430_193251262.jpg
https://jf-it-services.de/public/PXL_20250430_193451181.jpg
https://jf-it-services.de/public/PXL_20250430_193548439.jpg
https://jf-it-services.de/public/PXL_20250430_194218865.jpg
Curiously, the manufacturing quality is pretty sloppy with mine as well. The silicon wafers are not exactly cut straight, there is a noticeable scratch across one of the segments, and on the other side of that same segment they welded the bond wire basically on top of one of the LED chips :-o
The imprint next to the red LED (error indicator?) says something like Y58 to a logo consisting of an S or two, and 1275. So I’d guess it is week #12 in 1975? If that S is a manufacturer’s logo, I’m lost.
Looking up 1975 vintage manufacturers, I came across this collector’s site: https://www.crazywatches.pl/trafalgar-led-1975 which might also contain the display the NTW picture is taken from.
I’ve got a few of these as well! I’ve always loved the way they look, there’s a certain charm to the distorted little digits. Mine are in a big old hunk of HP test equipment, obtained off of Ebay for 1/1000th the price it sold for new 30 years ago and somehow still working after a bit of tinkering. It also features some alphanumeric displays in a similar package using neat little 5×7 LED arrays.
Unfortunately a quick look with a microscope confirms that the dies in mine aren’t identical to these :) Hopefully someone can track down exactly where they came from.
I enjoy how we all dig into our little troves of this stuff when this sort of ware comes up. I have a few of the National displays (NSA1588a, NSA1298 and an unmarked integrated one with 16 segments per digit), and some Litronix, H-P, and no name ones. No exact matches, though.
With the exception of some very early displays like the Monsanto MAN-1, none of these use individual LED dies for the segments. The ware pictured and all of the Nationals have a monolithic substrate for each digit made of GaAs into which a dopant is diffused (later implanted) to form the LEDs; for the red ones, I think it is P, so they are called “gallium arsenide phosphide”. The comb structure is the aluminum contact for the segment anode; the substrate back contact is the common cathode. The comb blocks some of the light, as shown in Adrian’s picture; I guess this is similar to the problem of making front contact to PV solar cells.
I have a friend who may have a stash of bubble displays – I’ll try to visit him before the month is over.
I’ll post a comment separately on the little bond wire goof.
On the little wire scrap: I think it is just bonding mistake. For these old things, I suspect the wire bonding was semi-automatic at best, maybe fully hand made.
Tin whiskers are another matter. There is no tin present here (unless maybe there is an ITO transparent contact layer). And tin whiskers are smaller in cross section than the bond wires in these displays.
When I first started hearing about tin whiskers, I started looking for them, and it didn’t take long to find some! Nearly any tin plated item can grow them, especially copper or brass. Find some parts like that which have been sitting undisturbed for a few years, like a drawer full of old ring terminals and look with a microscope. I quickly found whiskers up to 10 mm long; a couple mm is more typical. Zinc and cadmium platings can also grow similar whiskers, and I’ve found both. Each whisker is a single crystal, and I find them quite beautiful!
These whiskers are of course a notorious failure mechanism in electronics, and there is a large literature available about them, with pictures.