Chosen Solution
I have a 21.5 inch iMac EMC 2544 (late 2012) that had a bad logic board. Well i replaced the logic board, replaced the old memory from the previous board and now when i try to boot the computer it gives me the one beep after every 5 seconds EFI tone suggesting that there is No RAM installed on the computer. Well there is in fact two sticks of Ram installed. I tried removing the new board again and switching the order of the sticks (both of same brand and memory size, again ill reiterate that the RAM now inside the machine is that of the old logic board that came with the computer.) I cant figure out why it would do this and since there is no boot at all it does not boot into hardware test mode.
Hi, maybe one bar has gone bad somehow during your upgrade process? Have you checked on it using only one bar at a time? Are both logic boards of the same kind? I would suggest entering AHT first, maybe it gives you some hint what could be wrong. It’s also a good idea to check on the ram by inserting it into an known good system (if possible). Cheers
1 beep = No RAM installed/detected 2 beeps = Incompatible RAM type installed (for example, EDO) 3 beeps = No RAM banks passed memory testing 4 beeps = Bad checksum for the remainder of the boot ROM 5 beeps = Bad checksum for the ROM boot block" If there’s an issue with your Mac, it might make one of these tones when it starts up: One tone, repeating every five seconds: No RAM is installed. If you recently replaced or upgraded your computer’s RAM, check to see if it was installed properly. If the issue continues, contact Apple Support. Three successive tones, then a five-second pause (repeating): RAM doesn’t pass a data integrity check. If you recently replaced or upgraded your computer’s RAM, check to see if it was installed properly. If the issue continues, contact Apple Support. One long tone while you hold down the power button: An EFI ROM update is in progress. This applies to Mac computers from before 2012. Three long tones, three short tones, three long tones: EFI ROM corruption is detected, and your Mac is in EFI ROM recovery mode. Newer computers automatically recover from a corrupted ROM; when this occurs, a progress bar appears on the screen during ROM recovery mode. Don’t disturb your Mac while the ROM recovery takes place. When recovery is complete, your Mac restarts.
