CRG | Macintosh SE/30 Simasimac fault on a brand new board! @CRG | Uploaded May 2023 | Updated October 2024, 4 hours ago.
After seeing my previous hardware adventures with Macintosh IIci, Derek reached out and asked if I'd look at his SE30 motherboard. This brand new board whic hhe built himself has encountered an enigma—it's showing the elusive simasimac pattern.

So let's see if we can figure out why this newly built board won't boot. Can we figure out what simasimac is... can we even decide how to pronounce it properly...

SE/30 schematics - github.com/mishimasensei/macse30mlb

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Music - Cathode Ray Gun by @Momentvm

Chapters
00:00 Intro
00:55 Testing the new board
02:54 Simasimac
03:37 Could it be a bad rom simm socket?
05:18 Could it be the ram?
05:38 Could it be poor connection?
08:20 After some reading
10:16 Back to basics, reset, clock
13:41 Could it be the chipset?
17:58 Reflow the sockets and refinish the chips
20:50 A problem
21:45 Another test
25:33 Swapping the expansion port
29:30 Trying to boot with some odd behaviour
31:42 Final test and look at the goodies
35:14 Conclusion and credits