The 86x family is a great tool for me too, it's a real swiss knife you can carry everywhere (despite the poor brightness/contrast of the 863 model).
For the owners (like me) of the little brother 863, it seems there's an easy way to add the 2 missing hidden functionnalities (component test and logic) from the 867. But now way for its backlight (except changing the display board).
For the 2 fonctionnalities, you need to carefully disassemble the GMM and extract the rotary knob from the front panel.
You'll find 2 little stops at the rear of this knob.
Erase one (the good one) stop in the aim to allow the rotation like a 867 model, with a simple cutter.
Re-assemble all.
It's finished, enjoy
