crwdns2936637:0crwdne2936637:0 crwdns2853008:0crwdne2853008:0 crwdns2918746:0crwdne2918746:0

Early 2011 Model: A1278 / 2.3 GHz i5 or 2.7 GHz i7 processor

crwdns2934591:020crwdne2934591:0 crwdns2934593:0crwdne2934593:0 | crwdns2947278:053crwdne2947278:0 crwdns2947270:0crwdne2947270:0

crwdns2933897:0crwdne2933897:0

ONE Beep at startup then all fine...

One beep at startup then all running fine. I went from OS X 10.7 updating one by one 10.8 10.9 10.10 10.11 10.12. Clean installs no additional software added. Currently on Sierra 10.12 ROM 87.0.0.0.0 / SMC 1.68f99 is this right?. I have tested with 4 GB SK Hynix RAM / 8 GB SK Hynix RAM, swapped them around etc, still with one beep. 8 GB RAM is detected in system info & no error codes. Likely the RAM or board is beginning to fail.... Updated to High Sierra 10.13.6 with all available updates and the beep is no longer happening (Restarted 10x).... weird.

I intend to use OCLP to update it to Catalina but worried on the boot ROM / SMC version not being updated to be compatible for OCLP to run smoothly or brick it.

crwdns2934081:0crwdne2934081:0 crwdns2934083:0crwdne2934083:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2853045:0crwdne2853045:0 crwdns2853046:0crwdne2853046:0
crwdns2889612:0crwdne2889612:0 0
crwdns2947414:01crwdne2947414:0

Review If your Mac beeps during startup

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

crwdns2934285:0crwdne2934285:0

crwdns2933313:01crwdne2933313:0

crwdns2934221:0crwdne2934221:0
crwdns2931211:0crwdne2931211:0 crwdns2931215:0crwdne2931215:0 crwdns2934225:0crwdne2934225:0
crwdns2934051:0crwdne2934051:0

crwdns2933897:0crwdne2933897:0

One beep is a RAM error that the POST diagnostics failed. While it may appear fine after booting the issue is a flaky RAM. Best to try a different set of SO-DIMM's to see if that fixes the issue. It could be some corrosion on one of the pins or the socket frame is not holding the SO-DIMM firmly.

I would see if diagnostics caught any errors if you can get it to run Apple messed up the firmware and never fixed it. Haven't tried any third party tools and they often run a walking program flipping different RAM registers which does take a bit of time (more with larger SO-DIMMs or multiple present.

crwdns2934105:0crwdne2934105:0

crwdns2853045:0crwdne2853045:0 crwdns2853046:0crwdne2853046:0
crwdns2889612:0crwdne2889612:0 1

crwdns2944067:02crwdne2944067:0:

It has stopped beeping after I upped it to HS 10.13.6 oddly.... 1 beep means 'help' 3 beeps means "I'm done" then :)

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

@danj Just crossed my mind, Each time the unit booted up (or most times) it was after I had updated the OS version one after the other, sometimes it beeped & restarted, sometimes not, can this be due to the firmware update included with the installation process? Long time since I had to do this long process with a unit that had (Originally 10.6.8) such an outdated OS as it's not good to jump from 10.6.8 > 10.12 directly.

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

crwdns2934285:0crwdne2934285:0

crwdns2934229:0crwdne2934229:0

livfe crwdns2934231:0crwdne2934231:0
crwdns2936625:0crwdne2936625:0:

crwdns2936751:024crwdne2936751:0 17

crwdns2936753:07crwdne2936753:0 27

crwdns2936753:030crwdne2936753:0 27

crwdns2942667:0crwdne2942667:0 27