Amiga DiagRom
After watching the 4th episode of @thejanbeta's recent Amiga 500 repair video series, I learned about the existence of a custom kickstart ROM that can diagnose Amiga hardware twitter.com/thejanbeta/sta…
DiagROM is created by John "Chucky" Hertell and available for free. diagrom.com
Free also means that you need to program the physical EPROM yourself. I plan to do this for my A600, but for the Amiga 1200 I wanted to try out GGLabs' F2R16 - Flash based ROM replacement
The difference is: regular old-school EPROMs can be erased and prepared for a re-programming by putting them under an UV light-source (like the sun). That's why many of them come with a sticker on top that covers the UV sensitive area.
Image by yellowcloud (CC BY 2.0)
The modern equivalent, flashable EPROMs work like flash memory, you can overwrite the contents over and over. You'll still need a chip programmer and a ridiculous amount of adapters, but I wanted to explore this option and even solder one of the adapters myself.
Image by With the GGLabs solution I'll be able to program my own AmigaOS kickstart ROMs in the future.
The DiagRom will help me fully test my Amiga 1200. It will likely save me a lot of time hunting down crashes due to chip malfunctions. The machine is 30 years old after all.
It will also help me test the Amiga 600, which I'm still planning to re-cap (replace all capacitors) on my own. I'll need assistance by a proper test tool.
Back the the DiagROM: The installation is straight forward. Open case, remove existing kickstart ROMs and add the new ones. (Amiga 1200, 3000 and 4000 got two chips because even and odd bytes are split up: "High" and "Low" banks)
After booting, you get to access the diagnostics menu.
CIA test was successful. This chip is known for failing a lot. IRQs all look fine.
After a full memory diagnostics the 320x200 Testscreen had a glitch. I'll need to figure out why this happens and if it matters.
Here's an 18 minute debug session with DiagROM v1.1: (no audio)
(YouTube Direktlink)