DosFox

Computers are binary but I am not.

All views are my own and do not represent my employer.

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npub1xzs2uxhswuw74ecteuejs43wxr4g4f2yz6r4tvxatz6h6kaf5qqqthgqe4

NIP-05 Address

Profile Code

nprofile1qqsrpg9wrtc8w802uu9u7veg2chrp65254zpdp64krw43dtatw56qqqpz3mhxue69uhhyetvv9ujuerpd46hxtnfduqs6amnwvaz7tmwdaejumr0dsl57q39

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relay.damus.io

nos.lol

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npub1xzs2uxhswuw74ecteuejs43wxr4g4f2yz6r4tvxatz6h6kaf5qqqthgqe4

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Last Notes

2026-05-08 20:27:51 UTC

I wonder, does anyone know if the microprofessor-ii used an off the shelf case, or was it more likely a custom case?
https://media.tech.lgbt/media_attachments/files/116/540/834/989/392/564/original/5b075b1b4c91b229.jpg

2026-04-29 18:49:27 UTC

My JLCPCB order arrived! Look at this lovely slab of FR4!
It's the #OSHintosh, an open source hardware 68000 Macintosh.
On a nice and cheap two layer PCB!
https://media.tech.lgbt/media_attachments/files/116/489/318/223/859/097/original/ec8a4579d1f24f32.jpg

2026-04-22 20:54:36 UTC

Really beginning to wish I had about a month off from work, so I could just hammer out creating a YACCintosh clone, as well as tackling a Macintosh ii compatible system.

2026-03-31 21:42:05 UTC

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no reason it shouldn't

2026-03-31 21:28:27 UTC

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Also cleaned up the FoxSCSI repository a bit!

2026-03-31 21:26:45 UTC

Also you know how I built a terrible Amiga, which in turn became the world's worst Macintosh ii?
Well I turned it into a PCB! But I also added an ADB converter and Macintosh RS232 Serial interface!
It's still terrible, but according to JLCPCB it's 50p per board, and I can run the Atari ST core, the Mac Plus core, or I could actually use it as an Amiga if I really wanted to!
https://github.com/DosFox1/Migatosh

2026-03-31 20:25:28 UTC

With #MARCHintosh coming to a close, I'm happy to report that the OSHintosh has now been released on github!
https://github.com/DosFox1/OSHintosh

2026-03-24 18:40:05 UTC

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I'll let you tell him about the DELTA

2026-03-24 18:13:36 UTC

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ah hang on the Quapple is a quadlink by quadram, but it's still an apple ii on an ISA card!

2026-03-24 18:10:53 UTC

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https://github.com/schlae/quapple

2026-03-24 18:10:14 UTC

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yep. The Quapple.

2026-03-20 15:12:40 UTC

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funny you should mention that. Three different people suggested that to me as well.
I decided against it, as if the apple logo is a no go, something that's referencing the apple logo is a bit too close for comforts.
At least with this "not a Mac" it was drawn free hand by myself!

2026-03-20 14:48:06 UTC

Alright fineee here's the slightly less risky logo for the OSHintosh
https://media.tech.lgbt/media_attachments/files/116/262/043/992/852/265/original/8074ac3ae15d0e1c.jpg

2026-03-17 22:19:02 UTC

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Maybe I'll design a board to trial this out. I'm almost certainly missing other things that will need to be routed, and it might even necessitate a ROM upgrade to the II to make it think it's a IIx.

2026-03-17 22:17:32 UTC

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SO! By sticking a 68030 down, with a GAL to generate !PAS onto a small daughterboard that fits over the 68020 and MMU connector on a Macintosh II, it should be possible to upgrade a Macintosh II into a quasi IIx, allowing you to run A/UX and add more RAM.
In theory!

2026-03-17 22:15:57 UTC

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Looking back at the schematics again, that PAS signal (physical address strobe) is used in a single place - the NuChip (the Nubus controller).
It's also worth noting that by checking the Macintosh II schematics, there are a handful of signals that are handed over to the MMU.
In the IIx, these additional signals are just held high by a few resistor packs, whilst the only signal generated elsewhere is the PAS.

2026-03-17 22:13:56 UTC

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So this equation is specifically as follows:
/o19 = /i2 * /i9
+ /i2 * /i8
+ /i2 * /i7
o19.oe = /i11
o19 is the single output, which is supposedly the !PAS signal.
i2 is !AS (address strobe), i7, i8 and i9 are FC2, FC1 and FC0 respectively, and i11 is !BGACK.
All of the inputs are signals directly from the 68030. The !PAS signal is meant to be generated by the 68851 MMU, but instead is generated here.

2026-03-17 22:10:15 UTC

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Probably not. The tech goblin has taken over my brain again.

2026-03-17 22:09:28 UTC

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Except... After converting the JEDs to equations, I found that they basically were identical.
The IIx PAL is only used to generate *a single output* from a handful of inputs.
Comparing it to the PAL used in the IIcx (which has a few other outputs) - we can see that the same equation exists in both the IIcx and the IIx.
This would mean that all I need to do is compare the IIcx schematic to the pinourt of the equation to figure out how Apple adapted the Macintosh ii into the IIx.
Make sense?

2026-03-17 22:06:59 UTC

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The IIcx is basically a crunched down IIx.
Sort of.
It has a single mystery PAL (that has been dumped!), which I was assuming would be identical to the one found in the IIx.
No such luck - they're different

2026-03-17 22:05:58 UTC

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Now this is where things get a bit... Interesting.
Theoretically replacing the 68020 and MMU with a 68030 is nothing new, there were quite a few accelerators that managed it.
Unfortunately the schematics don't really exist for these accelerators.
Or the IIx.
But we do have enough schematics for the Macintosh ii and the IIcx!

2026-03-17 22:03:14 UTC

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In fact, if you compare the Macintosh ii logic board to the Macintosh IIx (which replaced the 68020 with a 68030), you'll see that the routing between the two is pretty much identical.
The only real difference is that the 68020 and 68851 have been replaced by a 68030 and a single PAL.

2026-03-17 22:00:22 UTC

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Except what does contain a nearly identical MMU to the 68551?
The 68030.

2026-03-17 21:59:16 UTC

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The only problem is.... The MC68551 is bloody uncommon.
At the moment I cannot find any eBay listings for them.

2026-03-17 21:56:14 UTC

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Why do such a thing?
Well... Quite simply a standard Macintosh ii doesn't have a "proper" MMU, it has what's effectively a hardware shim - the HMMU.
This can be replaced with an actual Motorola 68851 MMU - which allows it to access more than 8mb of ram (I still have no idea if MODE32 works with an HMMU, I suspect not), and it also allows for A/UX to run.

2026-03-17 21:53:33 UTC

So I think I've figured out how to add a 68030 to the Macintosh ii, which would replace the 68020 and the HMMU.

2026-03-13 18:15:06 UTC

Well this is certainly interesting. There is now a verilog semi working IWM clone!!
https://github.com/lampmerchant/tashmachine

2026-02-17 09:53:01 UTC

The sentence "The UKs 2026 entry to Eurovision was fully unimpressed by my Apple Lisa Clone" is certainly a brand new sentence.
It's also absolutely true.

2026-02-14 17:15:46 UTC

"I wish I had a good project to work on"
*Stares at pile of unfinished projects*
"No not like that"

2026-01-21 21:15:25 UTC

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I haven't bought it
Yet?

2026-01-21 21:09:06 UTC

I have just managed to find a literal barn find PDP 11/05 for £160.
The hell is my life.

2026-01-20 22:53:31 UTC

So apart from the Macintosh, NuMachine and the TiExplorer - was there any other machine that used NuBus as an expansion bus?

2026-01-17 16:03:59 UTC

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many??

2026-01-17 14:41:16 UTC

I'm randomly reminded of that weird time on the Bad Site™️ (Tw!tter) when the official Adadruit account started blocking everyone who even mentioned them.
What was that all about??

2025-12-10 17:11:05 UTC

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I think you can probably use both - I'll imagine you'll be ordering enough of both to significantly reduce the cost of both the 16V8 and 22V10

2025-11-21 19:10:58 UTC

So just as I left, the connector for the experimental PDS RAM card arrived.
That's a project I'll have to get back to when I'm home.
https://media.tech.lgbt/media_attachments/files/115/589/264/982/684/461/original/295fafcc024ac72e.jpg

2025-11-07 19:30:37 UTC

Why do I have that need to build a PCB specifically for getting Rhapsody on it?

2025-10-30 16:31:06 UTC

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alternatively design an RP2040 into the board

2025-10-30 16:30:43 UTC

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yeahhhhh unless you use a micro usb to USB cable and have a simple passthrough on the main board

2025-10-29 14:57:24 UTC

EE horror stories - needing to design an RFID antenna.
Without a network analyser.

2025-10-27 20:18:57 UTC

The screen geometry is awful, but the macintosh 512Ke is back in the land of the living after a recap!
https://media.tech.lgbt/media_attachments/files/115/447/973/015/868/038/original/a910f81a63cfaa4b.jpg

2025-10-25 09:46:11 UTC

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I thought the upgrade was a direct result of the video ROM being upgraded?

2025-10-24 13:29:06 UTC

I have a really dumb experiment that I need to check.
If you had an unenhanced apple iie, and then put a Pico based VGA adapter in - would that support double high resolution graphics?
Logically the answer should be no - the ROMs in an unhanced IIe are missing the ability to drive the video circuitry at that resolution.
Yet the IIe VGA card theoretically intercepts the video data - so there's a slight chance it could work?

2025-10-21 21:54:51 UTC

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should be 338-6503, which is a 65C02 rebadge (https://www.cpu-world.com/CPUs/650x/Rockwell-338-6503%20(65C02).html)
So that should mean you have an enhanced IIe as well!

2025-10-21 21:49:48 UTC

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on what should be a 6502!
Supposedly that's a 65C02 variant?

2025-10-21 21:22:32 UTC

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wait does that say 6503?

2025-10-11 20:22:51 UTC

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cannot tell if that's sarcasm or not 😅

2025-10-11 20:14:33 UTC

Something I'm intrigued by - and I really should look into - is how difficult it would be to interface modern-ish SRAMs to the SE/30 and other Macintosh ii computers.
According to the memory map, the actual memory is perfectly flat and contiguous from 0x0000 0000 to 0x4000 0000.
Stick some SRAMs to the right address lines, track down the R/W signal from the CPU and the OE from the GLUE (or generate it locally) and call it a day?

2025-10-11 20:08:54 UTC

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I'm sorry?

2025-10-11 18:33:58 UTC

I like how my hobby has gone from "I'm interested in Vintage Apple Computers!" To "my hobby is reverse engineering Apple custom ICs"

2025-09-27 18:53:24 UTC

TwoOfThem.jpeg
https://media.tech.lgbt/media_attachments/files/115/277/768/793/958/374/original/29116e22f296dda5.jpg

2025-09-22 17:58:05 UTC

So if someone were to hypothetically design a replacement for the Macintosh SEs BBU - what would be a good name for it?

2025-08-30 21:49:09 UTC

Well it only took me about a year, but I've finally started building a Lisa DAC!
As the name suggests, this is an addon card for the Apple Lisa that provides it with Macintosh Style audio output when it's running Mac OS.
It's literally a Z80 SBC on an additional board!
This will bring the total CPU count on the Lisa up to four - 68000 main cpu, 6502 IO controller, COP402 microcontroller for low level hardware and now the Z80 just for sound!
https://media.tech.lgbt/media_attachments/files/115/119/905/791/350/297/original/92222907fcc0873c.jpg

2025-08-24 10:21:12 UTC

It only took me about two years, but My DEC J11 is actually running and executing code!
https://media.tech.lgbt/media_attachments/files/115/083/230/380/831/910/original/ac65d3875106f787.jpg

2025-08-13 17:46:09 UTC

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Thanks to @npub1x56…v6yk and @npub1pu6…p73t for helping me with this 😅

2025-08-13 17:43:50 UTC

I'm very very happy this worked for the first time! It's my first attempt at writing logic equations for a GAL.
It's a pretty simple affair, the outputs (the three LEDs) are latched when the 12 address lines are set to 0x806 (pulled high and low with resistors here, and then the enable line (green button on the fair right) is pulled low.
Currently driven by a 8mhz clock - I should probably check it runs at 16mhz.
Pretty simple - but I'm glad it works!
https://media.tech.lgbt/media_attachments/files/115/022/675/233/515/403/original/b1c274bd5d2aa78c.mp4

2025-08-10 14:13:07 UTC

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My main dumb idea is to add a USB floppy drive to a bluescsi, so you could give 1.44mb floppy support to systems that could only access 400/800k disks 😅

2025-08-10 14:11:40 UTC

I wonder if it'll be possible to add USB host support to the #Bluescsi.
I.E, adding images onto a USB drive that plugs into the Pico USB port.

2025-08-07 15:40:56 UTC

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if you're literally taking a track from the GPIO to the speaker and then onto ground - the least you can do is get the polarity fucking right

2025-08-07 15:08:23 UTC

I've seen some bad electronic design in my time - however this takes the cake.
It's a product with a sound element on it. Originally it was a piezo, but it was swapped for an SMD speaker at some point.
They:
1) didn't add a drive transistor or op amp - literally driven straight from the MCU pin.
2) didn't add a back EMF diode
3) didn't test the thing properly. Instead opting to test each board with a 555 timer running at 5v, with a tester that was literally held together by a rubber band and zip ties
4) got the fucking polarity of the speaker backwards

2025-08-02 22:41:39 UTC

This thing is utterly ridiculous.
It's a wooden Apple Lisa!
Inside is my second #AppleLisaClone
https://media.tech.lgbt/media_attachments/files/114/961/565/420/474/956/original/f7ac0c1a459385c4.jpg
https://media.tech.lgbt/media_attachments/files/114/961/565/676/121/954/original/09637944dab63e36.jpg

2025-07-26 21:36:45 UTC

Well, huh! The guy who made the nanomac (Macintosh Plus on a Tang Nano FPGA) also wrote a MODtracker for 68000 macintoshes!
https://github.com/harbaum/NanoMac/tree/main/NanoMacTracker

2025-07-26 17:41:36 UTC

I love how the options for Apple Lisa Hard Drives is literally "spend £220 on an original profile with 5mb of storage" or "build an Arduino based emulator for £10 that can support 20mb LOS or 2gb Mac os hard drive images"

2025-07-20 20:29:23 UTC

I wonder if any of the ROMs for the 8 bit architecture prototype Macintoshes have ever appeared online.
I know about the Twiggy Macintosh ROMs - but nothing earlier than that!

2025-07-18 17:37:43 UTC

I finally got sick of the cards in my #AppleLisaClone rattling around the place, so I laser cut a proper card cage for the chassis. Looks pretty good, and it's fairly sturdy as well!
https://media.tech.lgbt/media_attachments/files/114/875/438/087/621/036/original/adc034066b150645.jpg
https://media.tech.lgbt/media_attachments/files/114/875/442/183/060/190/original/92533bf605e1bf62.jpg

2025-07-17 19:10:28 UTC

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I suppose there is already the micro:bit, as well as the assorted variants of Microsoft makecode.

2025-07-03 12:54:00 UTC

Just completed a small PCB order!
One is a redesign of the TashTwenty HD20 emulator, so it can fit into a #MacPlusClone (or SE for that matter)
The second is an adapter for my Macintosh PC drive - I've got the SE driver board for it, the drive itself... But not the cable to the DB37 connector.
And finally is a TK2000 minimal power supply!
https://media.tech.lgbt/media_attachments/files/114/789/389/603/241/212/original/1384f1119dd0dede.jpg

2025-06-06 19:07:55 UTC

Apparently I now own a 9 track HP reel to reel tape drive.
Shönk for scale
https://media.tech.lgbt/media_attachments/files/114/637/982/027/137/405/original/0ea7fa145fac0fa5.jpg

2025-06-03 18:44:42 UTC

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I'm just frustrated and a bit sad.
I even said I wouldn't sell kits of the Plus as that goes against the license of the reloaded plus logic board.
Then someone rips all of my info off and claims it's their own work.

2025-06-03 17:30:25 UTC

Well this looks familiar 🙃
https://www.tindie.com/products/denjhang/macintosh-atxvga-module/

2025-06-03 16:02:46 UTC

So a nice little thing arrived in the post the other day - it's a prototype ITXplus from Max1zzz!
https://media.tech.lgbt/media_attachments/files/114/620/267/008/119/762/original/8c649743e9f1c7c5.jpg

2025-05-16 08:26:12 UTC

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That appears to be correct. I think the only issue I've ever ran into with that level shifter design is if it's a relatively high frequency signal that's being converted. A few khz is fine, a few MHz and it gets a bit... Mushy.
There's a decent application note from Philips here:
https://cdn.sparkfun.com/tutorialimages/BD-LogicLevelConverter/an97055.pdf
Worst comes to the worst, add a few test points either side so you can add a different implementation if needed

2025-05-09 19:38:19 UTC

I have the overwhelming urge to build a 4 bit TTL CPU.
Except I'm a terrible programmer.
So now I have the overwhelming urge to build a TTL implementation of the i4004

2025-04-16 21:00:44 UTC

Did a thing.
https://media.tech.lgbt/media_attachments/files/114/349/647/296/463/505/original/60ee62192d666935.jpg

2025-04-14 19:02:00 UTC

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Also does anyone else get that sweet sweet rush of serotonin when you finally repair something?
This thing has been on my to-do list since 2023 *at least*
So finally getting it repaired was worth it!

2025-04-14 19:01:00 UTC

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I just realised this is only the second time I've ever seen an IC fail for seemingly no reason before.
The first time was with my SE/30 - where a counter IC on the main logic board had been soaked in cap juice and failed.
Also coincidentally causing vertical collapse.
If I had a nickel...

2025-04-14 18:06:52 UTC

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After a bit of careful wrangling (with my left hand firmly behind my back and adjusting the height potentiometer with a plastic tool) we have the full screen again!
https://media.tech.lgbt/media_attachments/files/114/337/640/182/888/675/original/a0149eb729e8cd01.jpg

2025-04-14 18:05:16 UTC

Hurray! I repaired my Macintosh 128k!
This one was suffering from vertical collapse - basically just showing a single white line on the CRT.
After replacing a fair few components I finally found the culprit - the LM324N had died!
I'm not sure how a single output could fail (the LM324N is a quad op amp, and the other op amps seemed to be working fine!) bit regardless, I'm happy it's back in working order!
https://media.tech.lgbt/media_attachments/files/114/337/628/112/039/601/original/dc5795aadeb658ad.jpg

2025-04-12 13:51:03 UTC

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ah yes, but this is a UART adapter. The uart output will only have power, TX, RX and ground.
You literally cannot use CTS/RTS

2025-04-10 09:49:33 UTC

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annoyingly enough that'll work.
I guess it saves on solder time 😅

2025-04-10 08:28:39 UTC

I love it when a repair is simple.
I wonder why the mouse on my Atari ST didn't want to work
https://media.tech.lgbt/media_attachments/files/114/312/717/941/684/168/original/b92506fdb16ea88a.jpg

2025-04-08 22:05:45 UTC

What's the chance I know someone on here with a spare Macintosh ii logic board?
For science, of course.

2025-03-29 17:24:53 UTC

I have a faulty Macintosh 512k board. It'll checkerboard and then show this pattern.
ROMs tested in a working board. RAM appears okay.
Any ideas anyone?
https://media.tech.lgbt/media_attachments/files/114/246/883/263/350/896/original/8e6a40b5ac9d8477.jpg

2025-03-28 18:14:56 UTC

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honestly I was quite surprised to learn about it.
Admittedly my flat was also powered by the last operating UK coal power station

2025-03-28 17:58:31 UTC

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nahhh I'm an urban fox. Just near a river that weirdly has a hydroelectric power station

2025-03-28 17:25:39 UTC

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we can't. We're in rented flats.
Unless I build my own hydroelectric power station in the bath.

2025-03-28 12:17:51 UTC

I keep thinking about a conversation I had with my neighbour.
We were talking about how we both save electricity, and they casually mentioned that they have never turned their storage heaters on.
They "just suffer" over winter.
Whilst on the other hand they were fascinated that I intentionally don't have hot water - as I've never turned the electric heating tank on.
We're both in our mid 20s, both with decent wages, and both intentionally going without a basic need because we can't afford it.

2025-03-13 21:58:01 UTC

Just a nice simple #Marchintosh project today.
I finally replaced the broken key on my french Canadian (!) M0110 keyboard, and the missing keycap was also delivered today!
I took the opportunity to also completely disassemble and clean out over 40 years of gunk that had accumulated inside it.
I wouldn't say it looks brand new, but it's a hell of a lot better than when I got it!
https://media.tech.lgbt/media_attachments/files/114/157/348/844/142/776/original/485a80c894c0a78f.jpg

2025-03-12 14:10:13 UTC

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it's been completely recapped!

2025-03-12 13:53:58 UTC

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well that's odd

2025-03-12 13:35:33 UTC

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wait do you have a VRAM module

2025-03-12 13:23:38 UTC

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oh yeah LCs need a battery to display video iirc

2025-03-12 13:00:38 UTC

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don't forget to reset the PRAM!

2025-03-07 22:23:37 UTC

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oh naturally - in reality it's another Macintosh Plus board, however it's using the incredibly cursed Unitron 1024 ROMs

2025-03-07 21:52:08 UTC

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Oh and that is some welcome news - HD20 init works! We can access HFS hard disks!
https://media.tech.lgbt/media_attachments/files/114/123/358/251/301/840/original/9fb024802670a2d1.jpg

2025-03-07 21:12:39 UTC

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Back home and I've been able to confirm that the keyboard, mouse and RTC are all working!

2025-03-07 19:38:58 UTC

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I'm ridiculously happy with how the badge turned out. Unitron used the same logo font as apple for the apple ii (Motter Tektura), so I just had to install it to laser cut a new logo out!
https://media.tech.lgbt/media_attachments/files/114/122/836/770/886/207/original/5b0ae7a99767631f.jpg

2025-03-07 19:34:29 UTC

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And yes, I did make a case for it
https://media.tech.lgbt/media_attachments/files/114/122/818/961/935/020/original/63d56dbf479e75f6.jpg

2025-03-07 18:57:25 UTC

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After bad ram, a bad 555 timer (!) and realising I shouldn't mix ferrite beads and inductors - she's alive!
https://media.tech.lgbt/media_attachments/files/114/122/675/062/665/658/original/4e488e91ad8a987e.jpg

2025-03-07 17:30:17 UTC

One week.
It takes one week for a queer fox to build a Macintosh Clone
#Unitron1024Clone #MARCHintosh
https://media.tech.lgbt/media_attachments/files/114/122/331/703/266/074/original/49265954a3810579.jpg