Quote Originally Posted by Acetronics View Post
No decoupling capacitors anywhere ??? ... especially the magic 0.1µF between supply pins ???
Further ... having your config header could have helped, but surely "Top secret matter"
Yes there is a 0.1uF cap close to the VCC pin from there to ground. There is also a 100uF cap at the point that the supply enters the board (board is supplied by an external 5v source).

config:
Code:
        __CONFIG    _CONFIG1H, _HSPLL_OSC_1H
        __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
        __CONFIG    _CONFIG3H, _MCLRE_ON_3H
        __CONFIG    _CONFIG4L, _LVP_OFF_4L