btw. just replaced the MCU hoping it would be semi-dead - no change. Working out QFP without stencil is refreshing
25% of LA wiring. bad thing without socketed option is that I am unable to flip the board.
I have a Color Classic. It's behaving a bit weird.
First of all, when i plug it in it won't start. It seems like if I keep it plugged in for a few hours it suddenly starts working. I can boot it up by pressing the power button on the keyboard, but when it boots up, the keyboard and mouse does not work. I've tried many keyboards that are definitely working on other macs, but nothing seems to work on this one.
Does anyone have any idea? I already tried changing the battery.
It should be 500kbaud, but it's mostly just symbols at certain code points. I should really get a proper debugger some time...
Thinking about this more, I wonder if it might be a power problem: the Ethernet controller draws extra juice to transmit, and it might be enough to cause the MCU to do a brown-out reset if the USB power source isn't up to the task. I was thinking of adding an LED pattern on reset so you could see it, but if you tie into the debug line you should be able to observe a reset that way too.
Also, frequency of operation of the components. I would expect interference generated by a G3 to be significantly higher-frequency than from an older machine, because most of the bits are running faster. I remember that (according to Johan Johansson, anyway) when the IBM 1401 was introduced to Iceland, they used to play tunes on it by accessing memory at the right frequencies and tuning an AM radio beside it. I doubt that would work any more unless you had a multi-gigahertz AM radio...