Gregory's Server
it's time for another early-morning electronics flea market! it's at a new location this year. I arrived at 6am but they hadn't let the sellers in yet, so everyone was just waiting around.
|
here's an interesting question. in the days before ubiquitous quartz clock movements, there were mechanical clocks that used a solenoid or a motor to automatically wind up the mainspring. i remember hearing some clocks make a "clunk" sound every few minutes, or a growling sound once or twice a day. anyone remember that?
Show previous comments
 @tubetime That's actually a pretty old system. Way back Harrison already used an automatic rewind system to minimize the difference in rate due to different winding status. Of course, he used weights to drive that, but still. "Modern" electromechanical pendulum clocks all used a similar system, driven by electromotors. If you go to a clock museum, you will find plenty of those. Later models would use solenoids to directly drive the pendulum, in order to increase the Q factor. this is a Nuvistor! it's a super-advanced vacuum tube that could have beaten the transistor.
Show previous comments
  https://www.youtube.com/watch?v=uTHpJZ3qd-c check out this cool ancient vacuum tube photocopier.  @tubetime Which he then promptly, specifically mentioned - complete with link. Hah. Anyhow, that link to the newly digitised version of a programme I first watched aged 13 or so, when first broadcast... this book arrived without a spine (yes yes, cue up the jokes!) and so naturally i get to make a new binding for it. step one is to line up the pages, clamp it down, and drill holes. step two is to stitch the pages together. there seem to be a bunch of different techniques for that, but this is how i decided to do it today. i got a cute little IBM PS/2 Model 25! it has a built-in b&w monitor and MCGA graphics. but it needed a little work when i got it. 🧵 for teardown and inspection i had to remove the entire plastic case. the monitor inside is shielded entirely with metal held shut with security "flat" screws. no bad caps inside, no RIFA caps, nothing else looked damaged.  @tubetime Thats cool, my school bought a whole classroom of these for "keyboarding" class to replace the IBM Selectric typewriters, they didn't have internal drives though, they all network booted off a 386 PS/2 server with LAN Manager and Token Ring IIRC. It was pretty sweet, you could power all 20-25 on at once and they'd all boot in less than a minute. PC-DOS 3.3 and WordPerfect. cross posting from the birdsite: about those "rare" Los Angeles tornadoes...  @tubetime I heard about the tornado today and did some looking, and found a claim that there have been about 40 tornadoes in LA county since 1950. So: unusual. here's an interesting tool: the HP 548A logic clip. it goes on top of a logic chip and has LEDs for each pin so you can see what the inputs and outputs are doing. the HP 10529A logic comparator is also very interesting--you install a "reference chip" and it feeds it all the same inputs, comparing the outputs to see if they match or not!  a new arrival: a Thinkpad 700C! words cannot convey how uhh sticky the soft-touch paint has gotten.
Show previous comments
@tubetime Open Circuits is back in stock! find it at your favorite local bookstore, bookdepository.com (free intl shipping), direct from nostarch.com, or from the rainforest website.  The mouse lays with its back off, its belly baking under the hot desk lamp, beating its pulse generator trying to turn itself on, but it can't. Not without your help....
Show previous comments
@tubetime I wonder if they’ve ever considered starting at 10AM instead of 6AM. I bet that would eliminate the complaints. this 486 motherboard has ISA, VLB, and PCI slots!
Show previous comments
 @tubetime I believe I had this board back in 1996. We used to refer to boards like these as VIP-motherboards, short for Vesa/ISA/PCI.
Show previous comments
 @tubetime I feel like as many of these ended up as SciFi movie props as were bought for their intended purpose @tubetime Have a SYM as well, but when I got it from ewaste almost 30 years ago, I thought, great 65xx parts to harvest. you know how the rev A 6502 from 1975 had a bug in ROR? turns out not to be true. https://youtu.be/Uk_QC1eU0Fg
Show previous comments
 i've reverse engineered most of the Game Blaster, Creative's very first sound card. check it out. https://github.com/schlae/game-blaster the challenge remaining is the mystery chip. it could be a gate array device, but i suspect it's off the shelf.  @tubetime huh, how does this relate to MUS-1099: I guess this is missing the ID logic? I built one of those cards and it's working pretty well (for Scumm-games at least): https://www.youtube.com/watch?v=bSW95JPUE4k what is this chip? the pinout is similar to a 6520 PIA. the DBx lines are bidirectional and connect to an 8-bit CPU or MCU data bus. pins 21-29 are control lines, maybe chip select, internal address, etc. there's a chance it is a PLA, but I don't know of any in a 40-DIP package. it also reminds me of some of the 82Cxx interface chips.  hey if you want better news coverage of that dang balloon, follow @Stratoballoon on the birdsite. bet you didn't know a similar balloon just overflow costa rica. 
Show previous comments
@tubetime No clue, but here in the UK the choice of weapon are the bloody wood screws. |
@tubetime This looks like it could be an album cover.
@tubetime @foone I was there a bit later.
@tubetime Where was it this time, and how did you find out about it?