Reverse Engineering the Macintosh LC Logicboard

Mr. Fahrenheit

Tinkerer
Founder
Sep 2, 2021
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Can’t wait to see it!! I’m sure you will post pics of the blank PCB the moment you get them. If you don’t… shame on you!! 🤣
 

max1zzz

Moderator
Staff member
Sep 23, 2021
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Oh don't worry, you can rest assured the very first thing I will be doing once they are ou the packet is posting a picture on here :)
Whoops, forgot that one...... :)

However, I can now post a picture of a fully assembled V1.2 board:
IMG_1797.jpg


The good news is that it works just fine! No patch wires and no weird NVRAM issues :)
 

max1zzz

Moderator
Staff member
Sep 23, 2021
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So the LC board currently has no schematics available, I thought it's about time that changes!
LC_CPU.jpg

This is going to take ages.... I have got used to how easy it is to work in sprint, going back to using KiCad is kind of painful. That single simple page took a few hours to draw (And I just noticed I missed the label on BERR) and I didn't even make the 68020 symbol form scratch (it's a modified version of the PGA symbol from Sakura-IT available here) I hate to think how long the symbol for the V8 will take to make!

If this turns out well I'll look at making new schematics for the Plus, LC II and LC III too :)
 

max1zzz

Moderator
Staff member
Sep 23, 2021
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And we have schematics!
I have literally just finished drawing these and have not extensively checked over them so there will likely be errors (If you do find any let me know and I'll fix them :) )
 

Attachments

  • LC_Schematics-V1.0A.pdf
    713.9 KB · Views: 405

max1zzz

Moderator
Staff member
Sep 23, 2021
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Board layout files, as well the the KiCad files for the schematic are now available :)

These are provided under a non-commercial license however if you provide repair services and want to provide these boards (Or want to use them for any other commercial purpose) please contact me
 

ace192

New Tinkerer
Jul 5, 2026
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Hey folks,
This is a long way back, but is the LC board good to use? I want to order one - this is great work!
 

bakkus

Moderator
Staff member
Mar 18, 2022
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Hey folks,
This is a long way back, but is the LC board good to use? I want to order one - this is great work!
The design is known to work, yes :)

You will probably have to order your own boards through something like JLCPCB or PCBWay, unless someone has one left over from previous projects.