Chosen Solution
I need a work around for this fan - to power it via usb or the optical drive plug (maybe in parallel with optical drive fan). What is the input voltage? Is there a wiring diagram for the connector? ie, which wires are power, ground, and data in/out? Update (01/20/2019) e) image of the connection in question ( plan and section - 2 images)
f) voltages across the pins and to ground (heat sink and female connector base metal visible). [image| Update: The image of the voltages above is incorrect. Measured at better location with DVM: Pin 1 – 6 volts to grd Pin 2 - grd Pin 3 – 0.3 volts Pin 4 – 0.0 volts I verified readings three times over several minutes. These reading while machine was operating. I reassembled the display and have it running to see if perhaps the OS will turn on this fan once it heats up a bit…ran a movie for 30 min – cpu area temp incl heat sink stayed about 50C.
For starters you can’t share the fan port to support two fan’s between the load being to great for the circuit the systems SMC won’t get the correct signals. How about fixing the root issue vs working around it? I would start off running diagnostics to see what error pops. I would also inspect the logic board for damage. Paste a few pics here on what looks off as well the diagnostic error if you got one. Do you know how to read a schematic as well as use a DVM? You might want to look through Louis Rossmanns vids on YouTube see what you can glean out of them that will help you here. Update (01/21/2019) Review this schematic
I would check Q5700 as I suspect its blown.
