Reconnaissance: Modern Diagnostics for your Classic Mac

[Durosity]

This is truly astonishing work! I'm looking forward to the Iici being added, Ive got a very problematic one of them.

 

[@RetroByte]

Great help for everyone who wants to repair their Mac!

I'm looking forward to new models for testing.

 

[jack 68k]

I am finalizing work on a big update which I hope to have ready in the next week, which includes support for the IIci @Durosity

 

[chuck.dubuque]

Will Reconnaissance work with Macs with 3rd party ROMs? Or should I go back to stock ROM before using the tool?

 

[joevt]

Will Reconnaissance work with Macs with 3rd party ROMs? Or should I go back to stock ROM before using the tool?

Reconnaissance depends on the diagnostics mode in the ROM. The Mac has to work well enough to run that code. If the 3rd party ROM doesn't bypass the diagnostics, then it should work. But don't some of these ROMs skip the diagnostics (RAM tests, etc.) to boot faster?

 

[rikerjoe]

#MARCHintosh 2026 is here and I'm excited to share a project I've been working on.

Reconnaissance

Modern Diagnostics for your Classic Mac

reconnaissanceapp.com

You may know that many Classic Mac models have a diagnostics mode built into the ROM that you can access over a serial connection. But it's extremely cumbersome, limited, and there are a lot of sharp edges that make it difficult to do much practical with it.

Reconnaissance is a new diagnostics app that runs on your modern machine that makes it easy to run the ROM's built-in diagnostics as well as quite a few custom ones (some of which I have adapted from a certain diagnostic device that repair techs used to have access to...)

The first release supports the following models:

• Macintosh SE/30
• Macintosh IIsi
• Macintosh Iicx
• Macintosh II
• Macintosh LC III

Support for more models (notably IIci) will be coming very soon, as well as a public release of full source code and SDK so others can develop custom diagnostic plugins in 68K assembly or C using modern development tools.

The app runs on macOS 14 Sonoma or later, Windows 10, and Windows 11. There's a lot of cool stuff to come and I can't wait to share the next update!

Check out this related thread about USB-serial adapters and cables

https://tinkerdifferent.com/threads/usb-serial-adapter-and-cable-options.5099/

Happy #MARCHintosh, everyone!
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Wow, this is so cool, Jack! I’m curious if you have received feedback on your tool working for units where the TechStep refuses to connect. I have two SE/30s that a recreated TechStep won’t connect to, but the TechStep works fine with other models in my collection. Great work!