Some HP-50G Questions

[Zaphod]

(12-03-2018 05:52 AM)cyrille de brébisson Wrote:  I do not remember the 50G mechanical. At one point this "hole" gave you access to a piece of bendable metal that was also the back EMC shield of the calculator. That grounded shield would bend down to the PCB and contact it when pressed. Closing the circuit and causing the reset. This explains the "shininess". But it might have been on the 49, not the 50. Other calcs like Prime use a switch.

Having just prodded one of my 50g's here, from the feel of it I agree the 50g uses a springy metal plate 'switch', not an actual tact switch.