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Jun 17, 2020 14 tweets 4 min read Read on X
let's take apart this old chart recorder!
umm, that's a lot of analog! mostly ceramic DIP packages, too.
the LED bargraphs are driven by two FPGAs and a whole pile of latches.
there's... even more boards underneath.
next layer: even more FPGAs. some ROMs too.
the processor board has an Intel 186 on it! just what I suspected.
feast your ocular orbs on this very old Intel flash memory chip, complete with 80s logo.
the bottom board controls the thermal printer. lots of GALs, FIFOs, and SRAM.
this is the fattest little delay line i've ever seen
looks like the onboard EPROM is just a bootloader. the real software is in the two flash memory chips that are soldered down. 🤔
check out the memory card in this thing. it is not PCMCIA, it's something called Melcard and it has a cute little shutter covering the edge connector.
gonna try to dump the flash memory. too bad it's soldered down--wait
oh, there's german in the flash! 256kB of text and code.
all right, can any of you think of a reason *not* to part this thing out? the rubber roller is turning into goo and staining the paper.

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More from @TubeTimeUS

Jun 13, 2023
here's a weird object! it's some kind of foot pedal with an IBM logo. is it for a sewing machine? electronic synthesizer? what do you think? 🧵 Image
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amazingly enough, I found something with the mating connector on it! but what is it? Image
Read 24 tweets
Jan 11, 2023
hey so remember the world's cutest oscilloscope i picked up last year? i think it's time to fix the probe socket issue.
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Read 11 tweets
Jan 5, 2023
in honor of Sim Wong Hoo, here's a quick historical review of the Sound Blaster! 🧵
but first we have to go back to their first sound card, the Creative Music System from 1987. (image credit: Bratgoul on Wikipedia)
this card has some special "CMS-301" chips. if you peel back the sticker, they have had their top marks removed. they're actually SAA1099 synthesizer chips made by Philips. Creative wrote music composition software for musicians on the PC.
Read 23 tweets
Dec 31, 2022
Tube Time: a 2022 retrospective 🧵
(and stuff you might have missed!) Image
starting things off in january, i found a tube of super old 555 timer chips! i also decapped one of them.
i also started fixing up an old HP 150 computer. it's not PC compatible but it runs MS-DOS--how odd!
Read 65 tweets
Dec 29, 2022
today's mini project: fixing this Radius Thunder IV GX daughtercard. it looks fine, but... 🧵 Image
one of the chips has some broken pins! Image
looks like two of the pins got mashed and broke right at the plastic package. Image
Read 11 tweets
Dec 8, 2022
on the bench of healing tonight: my coffee grinder which decided to bite the dust. Image
symptoms: i push the start button and the motor just bumps a little bit and stops.
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Read 23 tweets

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