geoffm3
Veteran Member
My first A4000 isn't working so hot. 
It had some damage to the motherboard traces around the clock battery. I've cleaned all that up and I've identified most of the damaged traces.
I have also scoped out a few basic things with my oscilloscope but I'm a newb when it comes to the AGA chipset. I started first with the power supply. Looks clean, ripple is very minimal on all the supplies, and the _FAIL line is high after a power up. I see D31 and A31 wiggle briefly at startup (a few seconds) so it looks like it's trying to run code for a while and then stops. Definitely looks like enough to do a burst to fill up the caches and then it stops, so maybe it's getting hung in some failed state in the code and just running out of the cache in an infinite do-nothing loop?
Clocks are clocking, resets I've checked are good, but all I get is a black screen, and the power LED doesn't change brightness. I've done the obvious and cleaned up the CPU slot connection. I see the Fat Gary constantly clocking data out of the parallel-load/serial shift registers that connect to the mouse/joystick/option ports.
Unfortunately I don't have a keyboard for this machine, but I do have a mouse. I guess I could try holding down the left mouse button and see if it wakes up to the early boot menu, but I don't think I'm getting that far. It would be nice to see a disassembly of KS 3.0...
It had some damage to the motherboard traces around the clock battery. I've cleaned all that up and I've identified most of the damaged traces.I have also scoped out a few basic things with my oscilloscope but I'm a newb when it comes to the AGA chipset. I started first with the power supply. Looks clean, ripple is very minimal on all the supplies, and the _FAIL line is high after a power up. I see D31 and A31 wiggle briefly at startup (a few seconds) so it looks like it's trying to run code for a while and then stops. Definitely looks like enough to do a burst to fill up the caches and then it stops, so maybe it's getting hung in some failed state in the code and just running out of the cache in an infinite do-nothing loop?
Clocks are clocking, resets I've checked are good, but all I get is a black screen, and the power LED doesn't change brightness. I've done the obvious and cleaned up the CPU slot connection. I see the Fat Gary constantly clocking data out of the parallel-load/serial shift registers that connect to the mouse/joystick/option ports.
Unfortunately I don't have a keyboard for this machine, but I do have a mouse. I guess I could try holding down the left mouse button and see if it wakes up to the early boot menu, but I don't think I'm getting that far. It would be nice to see a disassembly of KS 3.0...
