Post Reply 
Dark patch growing in LCD screen
08-21-2019, 07:21 AM
Post: #1
Dark patch growing in LCD screen
I have a HP42S that I seldom use. It came to my notice that that there's a dark patch in the middle of the LCD that gets bigger with time. Presently, the dark patch which is elliptical in shape nearly covers the entire screen save the two ends. Other than that the calculator is working fine. Did anyone have the same experience what what did you do to resolve the problem? Thanks.
Find all posts by this user
Quote this message in a reply
08-21-2019, 07:36 AM (This post was last modified: 08-21-2019 07:40 AM by ijabbott.)
Post: #2
RE: Dark patch growing in LCD screen
The fix would require opening the calculator up and replacing the reflective backing on the LCD. There is a thread covering this process for a HP-22S: https://www.hpmuseum.org/forum/thread-12652.html

An alternative would be to replace the entire LCD module using a HP-17B or HP-17BII (but not a HP-17BII+) as a donor. (I'm not sure about the 17BII+, but since it is a reimplementation of the HP-17BII, I'm guessing the LCD module would be different.)

— Ian Abbott
Find all posts by this user
Quote this message in a reply
08-21-2019, 07:55 AM
Post: #3
RE: Dark patch growing in LCD screen
Ian Abbott,
Thanks for the prompt response. The link you posted is most useful.
Find all posts by this user
Quote this message in a reply
Post Reply 




User(s) browsing this thread: 1 Guest(s)