Amiga 3000 cold power on issues

[Betelgeuse]

I was having similar issues with my A1200.  Wouldn't boot at first startup but would eventually start and run fine.  Tried sorting it out but never did.....untill I pulled out my Blizzard '030 and replaced it with a PiStorm. Any boot issues vanished.  Could be your processor getting old...

Thanks, it is possible something on the CSMkII is causing the issue, but it's not the CPU as I have several and the behaviour is the same with different revs of 68060. I'll replace the resistor pack I'm suspectful of today and we shall see if it makes a difference.

[Betelgeuse]

Well, I've spent the entire weekend on this thing and it's starting to drive me boing! I replaced the oscillator, no change, replaced the 2 resistor packs near the ROMs, no change. The old ones tested OK, which I expected as I've never seen those go bad. BUT, pressing on the ROMs, either one, makes the machine boot, as does heating them. So I replaced those sockets, and it is more reliable but after a long power-off period it still won't boot, pressing on the ROMs quite firmly makes it boot. The sockets are new and connections seem to test out ok, and it always boots with the built-in 68030, so I think those are fine. I looked all around that area and see no issues. But, how many layers is the 9.2 rev A3000 board? Could it be a bad via or a trace in the board that's wonky? So frustrating!

[Betelgeuse]

Thanks! It seems that the issue is in the corner area near the ROMs so I'llf focus on finding what the cause is. On possibility is U354, which is a 74LS174 flip-flop, not sure what else in there could be causing the issue but I'll troubleshoot with localized heating and see if anything can be located.

[Betelgeuse]

Figured it out, should've thought of that at the beginning so I feel pretty dumb about it, lol! One of the EPROMs that has Kickstart 3.2.2 doesn't like being cold in combination with CSMkII, hi-rom specifically. Not sure why, both are identical and I replaced previous 3.1 ROMs with these. Warming just U181 makes the machine boot every time. Putting in original 3.1 ROMs also makes it boot every time with the CSMkII, even from cold boot. The combination of this particular EPROM and 3.2.2 and CSMkII makes it not work when cold booting. So nothing wrong with the A3000 itself thankfully! What an annoying issue!

[Betelgeuse]

Final update: Replaced the hi-rom EPROM with a new one and the problem is solved. It was just a bad EPROM.