Mayer, with all due respect, I beg to differ. I have one now in my shop with this problem. Logic board is working fine, external video is working fine, but backlight is NOT working. I swapped the logic board for a known good A1181 board (therefore re-using the old LCD, cables, etc.). In my case, the problem *IS* on the logic board. The logic board is to be repaired or replaced. Unfortunately, I don't see another way around it. I admit this is only the second time I've seen this, so it is rare, but I can confirm it *IS* a real problem. So is there a trick to repair of the logic board in this case? I'm putting this here in case someone, like me, already exhausted all other t-shooting. Fortunately, I have 2 A1181's and was able to install a working logic board to confirm that all cables and accessories are all working. The A1181 with suspected bad logic board seems to have a problem. Even wiggling the "backlight" cable going to the upper-left socket on the logic board also did nothing. Again, swapping in a...
Hi everyone! I'm checking this out, but it seems to me like they are using a thermistor, especially if jumping the 2 pins sends a "low temp" signal as I have read. THat means it needs to see a little resistance. Typically Apple has used transistors as temperature sensors, which is a cheap and very inaccurate way of doing it, but I guess "good enough". I think it would be much better to use thermistors. In this case I have tried a 5k thermistor in an iMac 2010. Admittedly it does have an SSD, but the fan is not revving and all temps seem OK even after having it on for about 12 hours doing work. YMMV. Try at your own risk, IANAL, some restrictions may apply, see rules for details, Member FDIC, past performance may not be indicative of future results, part of this complete breakfast. Know what I mean, Vern?
