Some HP-50G Questions

[edryer]

Hi

Thought perhaps I'd use this to clear up some existing questions i had about the 50G.
Many thanks for any replies.

1.
When I am in the situation that I get the trying to recover memory dialogue, I press "A" for Yes and nothing happens... this is on both my 50G's, the key themselves are fine, but it requires multiple presses before (sometimes) it registers. No on the other hand is immediate.

2.
From what i can see of the HP-50G reset hole from disassembly videos it isn't simply a hole but seems to be a switch that touches the PCB contacts. Is this the case? It's just that I was rubbing down the back of one of my 50G's with toothpaste (minor abrasive to take out scratches) and some went in the reset hole.. peering in it now looks white.... does this actually reach the PCB or is it sealed between the "switch" and PCB?

3.
When I view objects that are Matrices used to be listed (if I recall) as MATRIX, they are now listed as ARRAY... what is the distinction because they are Matrices that I have created (and manipulate) but not sure why they are listed as arrays.

4.
What are the common failures of a 50G? Keyboard, LCD?

Realize quite a few questions and appreciate any responses!
Thanks
Ed Ryer