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Tube🌞Time

here's the board in KiCad. there's only one little problem now...
2 Dec 2023 at 2:21 | Open on mastodon.social
24 comments
Tube🌞Time

one of the chips is a mystery chip -- it has been marked "862130" but that is not the real part number.
2 Dec 2023 at 2:22 | Open on mastodon.social
Tube🌞Time

the person who owns this board pulled the chip out and found this underneath! how rude... 😆
2 Dec 2023 at 2:23 | Open on mastodon.social
Tube🌞Time

these are the pin connections i've deduced based on the rest of the board design. this chip seems to take over the Apple II's address lines and it copies sound samples over to the four DACs on the card. almost like a DMA controller. hmmmmmmmmmmm. 🤔
2 Dec 2023 at 2:24 | Open on mastodon.social
Tube🌞Time

i've got it! it perfectly matches the pinout of the MC6844 DMA controller! mystery solved.
2 Dec 2023 at 2:25 | Open on mastodon.social
Tube🌞Time replied to Tube🌞Time

boards are on order, so stay tuned.

2 Dec 2023 at 2:26 | Open on mastodon.social
Tube🌞Time replied to Tube🌞Time
Fritz Adalis replied to Tube🌞Time
Scott replied to Tube🌞Time

@tubetime that’s almost suspiciously quick!

2 Dec 2023 at 3:32 | Open on poorlyrendered.com
Eric Vitiello replied to Tube🌞Time
mmu_man replied to Tube🌞Time

@tubetime now *that* is fast delivery!

2 Dec 2023 at 3:50 | Open on m.g3l.org
Steve Syfuhs replied to Tube🌞Time
Bjornsdottirs replied to Tube🌞Time
Tony Arcieri 🌹🦀 replied to Tube🌞Time

@tubetime you’ve heard of an op amp but what about a pop amp???

2 Dec 2023 at 22:23 | Open on mas.to
Tube🌞Time replied to Tube🌞Time

got some parts in from China, but I need to test them to see if they actually work. they've been painted and remarked (of course 😑)
12 Dec 2023 at 0:13 | Open on mastodon.social
Tube🌞Time replied to Tube🌞Time

the ADC was tricky to test. one of them was bad and had some stuck outputs.
12 Dec 2023 at 1:00 | Open on mastodon.social
Tube🌞Time replied to Tube🌞Time

I wonder if it'll work? I'll have to fire up the Apple II to find out.
12 Dec 2023 at 2:14 | Open on mastodon.social
Chris Snyder replied to Tube🌞Time

@tubetime I like the “Apple II goes here” silkscreen.

12 Dec 2023 at 2:17 | Open on hachyderm.io
Rue Mohr replied to Tube🌞Time

@tubetime "Apple II goes here" ok, now I know you made it... I can guess its a super-rare IIe card that nobody has seen the likes of since the day after it came out...

12 Dec 2023 at 4:11 | Open on infosec.exchange
Benjohn replied to Tube🌞Time

@tubetime :-) Amazing. Before buying are you able to simulate the board, and is that useful?

2 Dec 2023 at 6:15 | Open on todon.nl
Tube🌞Time replied to Benjohn

@benjohn there aren't any models of the larger chips. it's easier to just make the board and try it out irl!

2 Dec 2023 at 6:20 | Open on mastodon.social
Mäh replied to Tube🌞Time

@tubetime 👏 Nice, how did you find it?

2 Dec 2023 at 10:06 | Open on chaos.social
David W. Jones

@tubetime I used to have an old Xenix multi-user system that contained a *lot* of chips. Like a full megabyte of memory on a single board (12" square) with dozens of chips. Plus chips on the mainboard, chips supporting the system bus...
While I never wondered what was under them, I was sorely tempted to unsolder them, stick antennae and googly eyes on them, and sell them on Etsy as "computer bugs"...
Thanks for the memory.

2 Dec 2023 at 6:15 | Open on mastodon.social
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