Hey y'all,
I work in the film industry, I have a good understanding of electronics and I design my own PCBs but I've never fixed an iMac logic board.
I am experimenting with battery powering my iMac.
I found that without the 7-pin flat data cable connecting the PSU and the logic board the iMac will work as expected but the CPU fan and the CPU will be pinned to max.
Then after some testing I figured out that pins 4 and 5 of this flat data cable are SNS_ACDC_N and SNS_ACDC_P, which if I'm not mistaken are two temperature sensors.
While measuring and testing things I have accidentally shorted these two pin (4 and 5), which resulted in the iMac shutting down and restarting and now even if this 7-pin data cable is connected the CPU fan and the CPU are pinned to max, like when it was missing those two temperature sensors.
So I suspect either one of those PSU temp sensors got damaged or something on the path to them.
I got my hands on an old iMac schematic which suggests these two temp sensors go to U5600, so maybe that could have gotten some damage?
Please help me troubleshoot and fix this problem.
I work in the film industry, I have a good understanding of electronics and I design my own PCBs but I've never fixed an iMac logic board.
I am experimenting with battery powering my iMac.
I found that without the 7-pin flat data cable connecting the PSU and the logic board the iMac will work as expected but the CPU fan and the CPU will be pinned to max.
Then after some testing I figured out that pins 4 and 5 of this flat data cable are SNS_ACDC_N and SNS_ACDC_P, which if I'm not mistaken are two temperature sensors.
While measuring and testing things I have accidentally shorted these two pin (4 and 5), which resulted in the iMac shutting down and restarting and now even if this 7-pin data cable is connected the CPU fan and the CPU are pinned to max, like when it was missing those two temperature sensors.
So I suspect either one of those PSU temp sensors got damaged or something on the path to them.
I got my hands on an old iMac schematic which suggests these two temp sensors go to U5600, so maybe that could have gotten some damage?
Please help me troubleshoot and fix this problem.