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vacuum tubes, vintage computers, the MOnSter6502, cross-sectioned electronic parts, memes, and other detritus. BNC stands for Baby Neill Constant.
otaria123 Profile picture Ross Grayson, MPH, CIH Profile picture fche Profile picture Steve Pick Profile picture Dan Gillespie Profile picture 6 added to My Authors
5 Nov
here is part of the payload electronics from the Explorer 8 satellite (1960)! look at all the machined phenolic, colorful hand-tied wiring harness, and the stacks of round circuit modules! 🧵
there were apparently two of these columns of electronics. someone's taken apart the second column and we can have a look at some of the modules inside. they are *glorious* 🥰
i was expecting Explorer 8 to look pencil-shaped but it actually has this sort of bulge in the middle. i can't find a diagram showing how the stacked electronics were placed inside.
Read 35 tweets
23 Oct
this Tesla SUV ran into a traffic barrier at 70mph while on Autopilot. how could this happen? there are 3 major contributing causes, and they're *fascinating* Image
before we dig into the causes, let's set the scene first: the southbound 101 freeway at the intersection of 85. there is a left exit ramp so commuter-lane traffic can get to the 85 southbound commuter lane. Image
the Tesla was in the commuter lane, then departed that lane and headed into the strip of roadway (called the "gore") leading up to the median, crashing into the barrier. Image
Read 37 tweets
20 Oct
this ought to take a while to print. Image
not too shabby Image
that took 7 hours to print 😂
Read 4 tweets
18 Oct
in 1990, a tiny company nobody had heard of, Cadtrak, sued Commodore for patent infringement and won. Their company CEO bragged that he put Commodore out of business! Commodore's downfall took more than just that, but who was Cadtrak, and what was their patent? 🧵
first, the patent. 4,197,590, filed in 1978. it described a method for drawing a cursor and then erasing it again without having to store a copy of the background. this was a simple XOR operation.
you see, with an XOR, a '1' bit in the cursor caused whatever graphics were on the screen to get inverted. XOR it again with the same bit, and it gets inverted back to the original state. a '0' bit made no change. this saves RAM, since you don't need to keep a backup image.
Read 25 tweets
17 Oct
i'm testing more vacuum tubes this afternoon. as you do...
don't use soap or water to clean a tube, the numbers will come right off. instead I just gently wipe it with a cloth.
first step is to find the tube in the little roll chart built into the unit.
Read 10 tweets
17 Oct
welp, i finally broke down and bought my first 3d printer! this one is an Ender 3. 🧵
it comes in a flat pack, this is basically like the Ikea bookshelf of 3D printers.
there are two layers of parts in this box!
Read 18 tweets
9 Oct
all right, this is a new one. a EULA on...fruit?!

'the recipient of the produce contained in this package agrees not to propagate or reproduce any portion of this produce, including "but not limited to" seeds, stems, tissue, and fruit.' Image
some folks think I faked it. it's real. it's even printed in French on the other side ImageImageImage
as for the fruit itself? not that great, they're just too sugary for my tastes. but hey, i'd never had them before.
Read 7 tweets
7 Oct
looking through some old photos, i found some neat pictures of IC chips. this one is a 7805 regulator. Image
8755 16K EPROM + GPIO Image
Intel 8080 CPU.

(this one is from National, i think they were a mask licensee) Image
Read 12 tweets
5 Oct
this is one of the world's first electronic calculators, the Friden EC-130, which came out in 1964! it's a really fascinating machine, so let's look at it in more detail. 🧵
you could buy it for about $2100 back then (about $20K now!) isn't it pretty though?
let's take a closer look at the screen. these are not LEDs or vacuum fluorescent displays, this is actually a CRT!
Read 51 tweets
1 Oct
this neon lamp should never light up! there's a fascinating reason why... 🧵 Image
ok so what is the circuit? this is a 3Com Etherlink card from the late 1980s. you can see the neon lamp in the lower right. actually there's a bunch of other interesting things going on but first, the neon lamp! Image
the circuit on the right side of the Ethernet card interfaces to the external AUI transceiver (the 15-pin D-sub) or a coaxial 10Base-2 network. the whole circuit is isolated by those two transformers, and i've put a red line so you can see no traces cross over. ImageImage
Read 14 tweets
25 Sep
this video landed in my youtube feed this morning. give it a watch, but try not to get too angry; there are some good lessons to learn. 🧵

this is the IBM 7496 Executive Workstation. i've never heard about it before, and it's probably quite rare. but rare doesn't necessarily mean valuable. Image
looking at the machine, it has some odd features. the tilted power jack is unusual; they must have run out of room in the case. Image
Read 55 tweets
24 Sep
this desk fan is 85 years old and still running strong. how would YOU design an electronics gadget to last 100 years? what components would you use? what potential failures would you expect?

bonus: how would you make it last 200 years? how about 500 years? Image
thanks for all the responses. i noticed some interesting patterns:
✅assume humans are around the whole time, so make it easy to repair. *lots* of subtlety to unpack on this one.
✅material choice is critical
✅keep it as simple as possible, but as complex as is needed.
honestly i didn't think of the repair thing even though it may seem obvious. i guess i was thinking about a device that could survive 200 years in a dusty closet. but repair is very important!
Read 32 tweets
21 Sep
this afternoon i built a really clever radio transmitter using a circuit i found in a book. it's really quite ingenious, so let's dig into it a little bit...
first, the book. it is "Communications Projects" in the Engineer's Mini-Notebook series by @fmims! i bought this maybe 25 years ago from Radio Shack.
here are the plans. i'll dig into the details of the circuit in a bit, but let's go through the construction a bit.
Read 46 tweets
18 Sep
welcome, new followers! you're probably here because of my PG&E thread, but there's a lot more stuff going on here. (🧵)
first up is the MOnSter 6502, the world's largest 6502 microprocessor. (you may have seen my pinned tweet about it). the 6502 is a microprocessor that was the heart of the original NES, the Apple II, the Commodore 64, the BBC micro, and more.

the MOnSter 6502 has a website, we were going to crowdfund and build more, but then COVID threw a big wrench into those plans. someday though. Image
Read 36 tweets
16 Sep
this electrical transmission tower has a little problem. can you spot it? actually, it's not a small problem--it cost us 16.65 *billion* dollars and caused the deaths of 85 people. Image
here's what it is supposed to look like. a transposition tower rotates the relative position of the three phase wires. this is done to balance the impedance of each of the wires so that one of them doesn't hog current. Image
here's the problem. the jumper conductor (the horizontal piece that brings a conductor from one side of the tower to the other) has fallen down. you can see the insulator dangling (circled.) but why did it fall? Image
Read 49 tweets
10 Sep
time to start reading another set of magazines! this time it is Electronic Design. this issue is from February 1969. based on the cover, this one looks very promising. Image
you can follow along by finding the PDF scans here:…
and right off the bat, nixie tubes! Image
Read 92 tweets
4 Sep
here's a fun piece of (very) 1990s hardware: the Snappy Video Snapshop, from a company called Play, Inc. it is a video digitizer, so video goes in one end...
...and the other end plugs into your computer's *printer* port! no USB back then, so this was how many peripherals connected to your computer, including CD-ROM drives, tape drives, even network adapters.
let's try it out! i found the software, thanks to…
Read 65 tweets
3 Sep
The new Intel logo represents a dramatic simplification of the Intel brand identity. Crafted with an underlying geometry, the logo has a refined symmetry, balance, and proportion that is understated and -- some may say -- iconic. Image
rejected versions ImageImageImageImage
more rejected intel logos ImageImageImageImage
Read 8 tweets
2 Sep
you've never seen this D-sub connector before! it is a 36W4. Image
the big pins can be solid (for power), coaxial, or even high voltage (with a protective plastic sleeve).
or maybe you only need three power pins, but with the middle one of the opposite polarity Image
Read 13 tweets
1 Sep
it's time to take a crack at fixing my other logic analyzer, this one is an HP1661A. Image
symptoms: fan turns weakly, no CRT filament, and no activity. it's mostly dead. but mostly dead is slightly alive! Image
pulling these plastic rods releases the power supply module Image
Read 25 tweets
29 Aug
i didn't have a terminator for a 1/4" audio jack, so i had to improvise a bit with some adapters Image
taken apart. see any connectors you don't recognize? Image
Read 4 tweets