I have a NOS Escom Amiga 1200. I bough it about a year ago. It was freezing and crashing soon after I put it into use, so I did recapping of the mobo. After this the system worked flawlessly for several months.
During the winter months I had to store the Amiga in a storage where temperatures matched the normal Finland winter outdoor temperatures -30 to +5 Celcius degrees. After putting the amiga back into use now in Spring, the freezing/crashing is back.
I already recapped again the 5V line 1000uf cap, because I suspected it had gone bad during winter. I've tested with three different power supplies, all of them stored in room temperature, no difference. One of the supplies is Amiga 500 PSU and two others Amiga 1200 PSUs.
The crashing is bad initially when turning on the power, it might be that the system won't boot at all before hitting keyboard reset multiple times or boots up to workbench but then after couple of seconds (or after longer while) the screen either flashes or goes black and mouse freezes. Keyboard reboot helps again.
After it does this about half an hour, power continuously on, the system becomes very stable. So it kind of needs warming up. But what can be wrong? Caps? But they were all changed a year ago and the 1000uF ones again last week. Could it be the small caps, 0.22uF etc. (are they tantalum or some such?)? I've only changed the recommended SMD and radial caps. I've checked the soldering on all caps, looks good. Mobo traces all look good.
EDIT: some more info. I've tried with various configurations: with/without CF IDE attached, with/without floppy drive attached, with/without ACA-1220 attached. I reseated kick roms several times. No change, symptoms are always the same. I've been measuring the 5V line with a multimeter just after the 1000uf cap, and it gives me steady 5.03V even when the freezing or crashing happens.
Also usually this crash makes whole screen to display mess (I use RGB Scart) and floppy drive ticking stops so I think the CPUs not running anymore. Could it be RAM issue as well?