Some 5 months ago, I got a 12c+ from you (4CY11705LP). Bad ENTER key, bad "1" key, unsatisfying keyboard overall.
In another thread on this forum, some three months ago, we seem to have reached the empirical conclusion that calculators from 4CY have lower quality keyboards than calculators from the other factory (CNA). They can easily be recognized by a slightly different key font, and, notably, by the uncommonly large "%" key sign see here and here .
In my case, after many contacts and much frustration with an incredibly inefficient HP costumer service (Brasil), I decided to open the calculator. It turns out that the circuit board was not sufficiently pressed down by the heat stakes. I thus introduced a felt pad on the "bad key" region, so that the back panel would slightly push the board down. Both keys are now working fine. It still is an overall lower quality keyboard, though :-(
The 15 LEs seem to be produced only on the CNA factory. That is probably why the general feel of their keyboard is always good. But, as we all know, problems with particular keys exist there, also.
Paulo
Edited: 10 Feb 2012, 3:54 a.m.