Package arrived, however I am now not confident that this will work. I removed my part last night and comparing the resistances of the two parts _off_ the board they are very similar -- both are around 8.2k ohms at the moment (28C in the room :o). So presumably the resistance difference on the board is due to some other broken part or maybe a short or partial short somewhere? I will try soldering in your part tonight anyway but I'm not holding my breath...
Looks like the trace from TH303 goes straight to the daughter board that the fans are plugged into, so I would guess the fault is on that board. (I think maybe the other lead is connected straight to the ground plane as I had more difficulty getting it desoldered.) Going further down the rabbit hole, don't suppose you have a spare daughter board you'd be interested in selling me?
Ok I've replaced TH303 and can report partial success? The internal temperature now displays as ~29C in the PowerChute UI. Room temperature is 27C, so this seems reasonable. Unfortunately the fans are still running all the time, even when on mains power and there is no/low load. Interestingly the fans turn off when I unplug from the mains and there is no load. If I unplug when there _is_ a load the fans still run. Maybe it thinks the battery is charging or something, but the battery is at 100%.
Howdy I have seen this counter intuitive behaviour - no fans with no mains supply provided there is no load on some SMX types. Did you say you have updated the firmware already?
I'd give it 7 days before doing anything else. If its still giving trouble then I'll hunt for a daughter board. I am not sure if the boards are keyed together on this range, which would bunker bust the idea.
Half way there though now you have reasonable temp readings!