Check and clean the connections on the card. The SIMM and CPU slot, for example. I take it the fan is still spinning fine? Try cleaning any dust out of the heat sink too.
The Apollo cards have terrible standard software (which can be worked around) but the hardware seems good.
I have an A1200 which runs unattended about 60 miles from me on an Apollo 1240/40 - it sent me this yesterday: "23:50:02, 9 days 13:55, load: 0.20, 0.03, 0.00"
9 days uptime
I fully expect it to last another few weeks before memory fragmentation means it requires a reboot.
