HP 41 DISPLAY cleaning

[aurelio]

I don't remember if there's already a discussion about this matter, but I wonder if is it possible to do something to "renew" or to clean the display of the fullnuts; mostly they have a yellowed look I don't know if from the smoke of users or just due to a natural process.
just once I disassembled one of them trying to repair the keyboard, but I was so worried in unsoldering /solder again the contacts and restoring the calculator that I forgot to give a clean to the trasparent cover to check if the problem was located there..... somebody knows the secret and succeded in doing it?

[Geoff Quickfall]

No access except for desoldering and resolding the LCD panel. Yes the PC. Contact traces can only take so much and can lift easily if you lift the contact to soon while desoldering.

Have you tried polishing the outside clear plastic lens with plastic polish to determine if the yellow in inner or outer surface.

[aurelio]

(10-07-2016 08:44 PM)Geoff Quickfall Wrote:  No access except for desoldering and resolding the LCD panel. Yes the PC. Contact traces can only take so much and can lift easily if you lift the contact to soon while desoldering.

Have you tried polishing the outside clear plastic lens with plastic polish to determine if the yellow in inner or outer surface.

Thank you Geoff, the first thing I tried..... with the NOVUS I use for scratches, but there's no way. I'm sure it's from the inside. I think I'll keep them with the witness of their age.....if it ain't broke, don't fix it (fragile posts were lessons for me)