Circuit Repair - 44 pin Microcontroller Expected Heat Output?
I am working on a Bluelab Guardian a TDS and PH monitor for aquariums and hydroponics. Total device power is 5v 1 amp. I suspect the previous owner hooked it to the wrong power supply and fried it. No response when supplying the correct 5v 1a
No visible damage on the PCB to make things easy. Many parts of the circuit have active voltage when plugged in which gives me hope it's not a total loss.
While checking the board with power supplied I noticed that the main 44 pin Microcontroller was getting quite hot - measured as high as 170F which seems high to me for such a basic chip.
This chip's model number is "PIC18F2423" - and trying to search through the documentation I couldn't seem to find anything about expected operation temperature so was hoping someone with general knowledge of basic chips like this would have an idea if that level of heat output might be an indication that it's fried. Any thoughts?
Since it stores the programming, if it's dead then there's nothing else I'd be able to do with this circuit so this seemed a reasonable place to start.
While investigating the circuit I did find a DC to DC converter which seems to be dead - has 5v coming in and no output. It's a 4 pin model with no "enable" pin so I believe I should have voltage out. I can definitely replace it just don't want to start swapping components throwing good money after bad if there's a chance the main microchip is fried.
Any advice or suggestions appreciated. Photos of the circuit attached.