Mid-2011 27" iMac random beep not from speakers

[yellowroom]

Hi,

My iMac is still going strong with a successful SSD upgrade and max RAM. All working well apart from a seemingly random, very annoying beep every few minute. The beep doesn't come through the speakers, but seems to come directly from the hardware/boards. It's a very short beep, a bit like when a smoke detector battery is going low. It goes away for a few hours and then comes back. No pattern to relate it to what the iMac is running at the time.

To be honest, it's been there several years now - before I did the SSD upgrade - and I used to be able to ignore it. However I am currently working from home so 8 hours a day of this is a bit wearing. Any ideas what it is? And how I can fix it?

Thanks in advance!

 

[Jumme_Cph]

To be honest Im not sure, so here goes nothing.

1) Reset PRAM and SMC. Still? Then..

2) Run Apple Hardware Test (AHT) to locate faulty components.

Error still not located?

3) since you already opended the mac, you probably know how to do this.
Open imac, disconnect DATA cable (not power cable) to the SSD.

with LCD completely disconnected and removed, position the imac chassis and LCD in such a way that you SAFELY can connect the top left cable (LCD temp) WITHOUT stessing the cable. Dont break the cable!

This allowed you to turn on the mac - without booting the SSD - and without speeding up the fans, because you have the LCD temp monitor cable attached.

Let the computer run for a while. Can you locate the sound? Is it from a fan? Did you keep the old HDD as well, is it from there (faulty HDD failing)??

IF you are unable to locate the sound - replace CMOS BR2032 battery as a last attempt, then close up mac and hope for further suggestions.