HP 48GX screen contrast

[Han]

(09-01-2016 01:53 AM)DavidM Wrote:  

(09-01-2016 01:39 AM)Han Wrote:  I have found that in almost all HP48's that I have opened the rubber piece pushing the keyboard contacts onto the pcb has decayed to some degree. Even if all keys work properly, I generally just go ahead and place another piece of foam behind it to help push the contacts even closer for good measure.

I have found that the 39G to be the most economical donors.

What type of foam do you use? And how do you obtain it?

Also, I could be dreaming but I seem to remember that something I've seen (maybe even your own online instructions) mentions that there are at least two different kinds of display connectors on the 48 systems. Is there a way to know before opening if the displays are interchangeable? I'd hate to start down this path only to find that the display replacement isn't possible.

I don't remember the specific type of foam, but it was essentially a very thin foam tape (yet thick enough) that I cut into the right size. (It resembles this: https://signobi.com/internalProducts/foa...m-tape.jpg)

And yes, the connectors for the screen (they look like rubber strips) are specific to that screen. It may be that two screens can interchange the connectors, but in general the grooves in which the connectors sit are the exact depth for their respective connectors.