1 year-old iMac dims automatically - not usual suspects

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1 year-old iMac dims automatically - not usual suspects

An iMac I bought new in May of 2019 (running Mojave 10.14.4) has been randomly dimming on it's own for week now. The usual suspects do not solve it:

1) "Automatically Adjust Brightness" is not turned on.

2) Resetting SMC does nothing.

3) I have reset my NVRAM / PRAM multiple times.

As for that last one: resetting NVRAM sometimes works. When it does, the brightness is normal for about an hour, then automatically dims again. Then you have to power down and repeat the process. But now, that doesn't even work.

This is barely a year old! Any thoughts on what to do next?

iMac 27″, macOS 10.14

Posted on Jun 30, 2020 4:12 PM

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rkaufmann87

Level 10

140,976 points

Jun 30, 2020 4:14 PM in response to Korbinopolis

When resetting the NVRAM please do so with all external peripherals disconnected.

Also, by chance is there any third party Antivirus, cleaning or other third party "MAINTENANCE" apps installed?

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1 year-old iMac dims automatically - not usual suspects

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