Mid-2014 A1502 MacBook Pro Retina 13 Platform Controller Hub stuck at

Hello!

This sensor temp is via Hardware Monitor, all other temps are within normal range

Info:

• Wiped the machine with a fresh Mavericks installation
• Did fresh thermal paste and blew out the fan (thermal paste was still fine/liquid and fan was clean but I did it anyway)
• Tried cleaning and reseating trackpad ribbon cable
• Tried disconnecting the webcam connector
• Reset the SMC
• Reset the NVRAM/whatever other ram is with P + R boot

Hardware Monitor is reporting that the Platform Controller Hub chip temperature (on the Apple SMC) is still reporting 127, which sounds to me like an error since the PC is not under any load and 127 is the max value of signed 6-bit? register
I'm sure it's a failure of the sensor in this chip but not sure what I can do to further fix this device.

I see now that replacement logic boards are roughly $95 shipped. The whole device is worth roughly $300 (I think). What do you guys think? Sell for parts?

I feel very comfortable with just about any kind of repair short of a re-ball (not ready to purchase that equipment, give me a few years).

Note: Another oddity I just discovered: I can get the full 900MHz out of the machine WITH an external HDMI screen attached. Without an external screen connected, the mouse’s position takes 7-10 seconds to update on the screen after moved.

I just got full permission from the owner to do whatever I like to it, no matter how destructive. If there were a way to manually override the PECI/PCH temp, I’ve been given the green light, but I don’t think there’s any way to do so.