Chosen Solution
I have gone through the previous messages about this issue: 3 short + 3 longer + 3 short beeps means EFI ROM checksum failed. I downloaded and created Firmware restoration CD 1.6 for iMac7,1 from Apple support. Turned power on and iMac sucked in the CD and ejected after 1 minute and started beeping cycles again. Questions: I burned the CD on Windows with PowerISO. Should I try burn the CD on Mac instead?It seem doing something with the CD. Or it’s hardware issues with the ROM or board that firmware refresh won’t fix? Any feedback welcome. Thanks. ps. I remove the screen and couldn’t see any bad connection and also replaced the lithium battery too.
Ok thanks I’ve managed to fix it. I stripped the machine down this morning. It would appear the CMOS battery was loose. The plastic that holds it in place has failed so replaced it with a new battery and used good old hot melt glue to hold the battery in place. Switched her on and heard the lovely Mac chime again. Put her all back together she’s working a charm. Thanks for your suggestions.
Sounds like the iMac didn’t like the created CD. That could be because making it on a windows system Vs Mac. It’s also possible the format of the CD was not correct. Can you make a fresh one on another mac system?
