Apple imac hdd fan control software#

If the input voltage on pin 3 is LESS THAN pin 2's reference voltage, then U5400 shorts pin 1 to ground. The circuit also produces a 1.5V pullup voltage from PP3V3_S0_SMC_LS through a voltage divider (R5402 & R5404).

The circuit produces a 1V reference voltage from PP12V_S0_SENSE through a voltage divider (R5400 & R5401) and delivers it to pin 2 of U5400. The above circuitry is common to all iMacs from 20. See the SATA power pinout reference table as needed: A 0603 or 0402-sized resistor should work just fine.Īfter soldering, be sure that pin 11 and all of your ground pins have continuity to one another (so pins 4, 5, 6, 10, 11, and 12 should all have continuity), and that they do NOT have any connectivity to the 5V pins (7, 8, and 9) or the 12V pins (13, 14, and 15). To modify the logic board and provide a permanent fix for the high fan issue, simply find J4511 where the SATA power cable for the hard drive connects to the logic board, and simply solder HDD_OOB_TEMP_FB on pin 7 to ground on pin 6 using either a solder blob or a 0 ohm resistor. Chances are these won't be going through too many drive replacements in the future. Modifying the logic board is preferable as it is a more permanent fix that will remain in effect through potential future drive replacements, but it DOES requires access to the backside of the logic board, so if you don't have the board pulled already it may be preferable to simply modify the drive itself (see below). YOU DO NOT NEED TO MODIFY BOTH ENDS, BUT NO PROBLEMS WILL BE CAUSED BY BOTH MODIFICATIONS BEING IN PLACE. On 2010- 2011 iMacs you can either modify the drive you'll be installing -OR- the logic board itself. You could also simply add a jumper between the two pins of J5400 on the logic board itself. The best solution is to simply snip the hard drive terminal off of the cable and strip and solder the two wires together. On 2009 iMacs, there is a separate two-wire cable that runs from the logic board to the hard drive and connects to J5400 on the logic board. If you connect HDD_OOB_TEMP_FILT to ground, the thermal trigger never occurs and the system will behave as it normally would with its OEM drive installed.

There is no such thing as HDD thermal sensor on iMacs from 2010 or 2011 - instead it's simply a thermal trigger sent by the OEM-installed hard drives.

Apple imac hdd fan control software#

These can be controlled by software like MacsFanControl or smcFanControl, but that's a poor workaround for an issue that can be addressed internally quite easily. If you replace an OEM drive in a 2010 or 2011 iMac, the fans in the system will go crazy.