Reverse Engineering the Macintosh Plus PCB

[volvo242gt]

That's just because the floppy drive is not hooked up, for some reason the icon doesn't flash on the plus without a drive present

I think mine (the former tafkar Mac Plus) does... I'll check later today. It currently is driveless.

Another idea for a future revision would be to hack in the necessary code and to swap a SWIM chip for the IWM chip to provide Superdrive capabilities to the Plus board.

 

[max1zzz]

Board layout, gerbers and scans are now on GitHub:

GitHub - max234252/MacPlus-Reloaded: 1:1 Reproduction of the Mac Plus PCB

1:1 Reproduction of the Mac Plus PCB. Contribute to max234252/MacPlus-Reloaded development by creating an account on GitHub.

github.com

As with my other designs these are provided under a non-commercial licence but if you are a repairer and want to offer transplant services (or have any other commercial use in mind) please contact me

BOM will be added soon, It needs a little cleaning up first

I haven't updated the ROMinated board as I still need to get around to testing it....

 

[Iesca]

Now that the board is reversed-engineered, would it be difficult for someone to make a new version of the schematics? Given that the ones currently floating around out there for the Plus are very low quality and hard to read.

 

[max1zzz]

Now that the board is reversed-engineered, would it be difficult for someone to make a new version of the schematics? Given that the ones currently floating around out there for the Plus are very low quality and hard to read.

That is actually something that is on my list of things to do
Unfortunately that list is very long so if someone else want to have a crack at it please be my guest!

 

[al kossow]

Now that the board is reversed-engineered, would it be difficult for someone to make a new version of the schematics? Given that the ones currently floating around out there for the Plus are very low quality and hard to read.

http://bitsavers.org/pdf/apple/mac/schematic/050-0159-A_MacPlus.tif

scanned from a blueprint I bought off eBay

 

[Iesca]

Oh wow, what an improvement! Thank you so much!

 

[Jockelill]

Fantastic work @max1zzz !! I recently started the task for making a new analogue board for the Plus, so first step was to remove all components and get a good scan. So here you go if anyone else wants to try it before I finish. I've also scanned the plastic cover. I also noticed the the scanner cut a tiny bit of the component side, I'll correct that when I'm back in office in early March.

 

[aihk]

Super job, well done!!


Or even just a 50 pin (internal) SCSI header would be useful.

Something else to think about... the Plus can be a pain with SCSI devices, since it doesn't supply TERM POWER. I know @erichelgeson had to make some mods to his BlueSCSI to try and overcome that. Would be nice if that could be done to address that..

I used your file to make plus, and there was a problem with the checkerboard.

 

[Mycroftecosse]

Hello. Apologies for any noob mistakes, but I am looking for help. I have a Macintosh Plus Replica PCB I sourced from eBay. A battery bombed donar Macintosh Plus board, and a Raspberry Pi Pico Breakout board to supply power and VGA out. I have a 3.5 external drive, and a BMOW Floppy Emu.
When the board boots there is a sort of bong, a black screen surround ”disky” (disk and ?), if I put a bootable disk in I get a happy Mac, still with a surround d black screen. The drive or floppy emu search for a few seconds then stops.
I saw Adrian Black’s video suggesting stuck on an alternate screen, and was a RAM issue. I have tried various other SIMMs and still the same black surround. I have tried R8 populated and 4x256kb, currently I have R8 populated and 2 x 1mb SIMMs and still the same.
everything is socketed - see the board.
Any ideas?

 

[Iesca]

I would have also recommended Adrian Black's video, but of course he was dealing with a memory expansion board problem if we're thinking of the same video. Have you looked at the Dead Mac Scrolls book?

 

[Mycroftecosse]

I would have also recommended Adrian Black's video, but of course he was dealing with a memory expansion board problem if we're thinking of the same video. Have you looked at the Dead Mac Scrolls book?

Thanks - I’ve tried the Dead Mac scrolls, and google, and RAM SIMMs seem to be the problem usually. Interestingly with just one bank selected I have got error codes for certain SIMMs, but still with the black border…. Which I think is the key

 

[Mycroftecosse]

Thanks - I’ve tried the Dead Mac scrolls (nearest is Pg 66 but unusable at flashy, and mine will go to happy Mac then unusable), and google, and RAM SIMMs seem to be the problem usually. Interestingly with just one bank selected I have got error codes for certain SIMMs, but still with the black border…. Which I think is the key. I tried Adrian’s trick with interrupts but could see anything on the screen but I’m using a Samsung TV so not sure if the effected pixels are off screen