Creeping black pattern on HP-11C screen
#1

My venerable 30 year old HP-11C is getting a black splodge on the LCD screen (when calculator is both on and off), and seems to be growing with age. A photo of the problem is below.


https://docs.google.com/file/d/0ByRUk1Zt3XiLTlpXdHJ0QVE5TEU/edit?usp=sharing

Can anything be done about this?

Larry

HP-11C photo LCD problem

#2

The only way to fix that is to replace the LCD assembly with another one from the same era. It can be from a 12C, which is of course the easiest to find.

On later units, HP changed the display multiplexing, so the displays aren't interchangeable with the older units. I'm not sure exactly when that happened.

#3

you should post a picture of the battery contacts. That would help forum members guide you on what era LCD you should look for.

#4

OK, here is a photo of the battery contact:
https://docs.google.com/file/d/0ByRUk1Zt3XiLZ1MzaWJlVkY5S3M/edit?usp=sharing
battery contacts

Also the serial # is: USA 2716A13463 (if that helps).

So what version of HP calcs can I get the LCD screen replacement from?

Larry

#5

Yours is a later model so you should look for a 12C with srarting serial numbers close to yours such as 24, 25, 26. I don't know how early you can go, but I am pretty sure these would have compatible LCDs. Good thing is there are plenty of 12Cs around.

edited to remove 27 & 28. Thanks Randy


Edited: 12 Apr 2013, 9:23 p.m. after one or more responses were posted

#6

A 27xx serial number indicates manufacture in 1960 + 27 = 1987; etc.

#7

I would avoid serials beginning with 27 and 28. They changed the 12C design late in 1987 and the replacement unit might well have the wrong version LCD. The 15C and 11C change followed the 12C sometime later in 1988.

The way to know for sure is be the number of IC's. Your 11C should have two and the LCD must come from a 12C with two IC's as well. If you open your donor 12C and see only one chip, the LCD is not compatible.



Possibly Related Threads…
Thread Author Replies Views Last Post
  Prime screen scratches - Use a screen protector Eelco Rouw 11 3,233 11-19-2013, 10:16 PM
Last Post: Eddie W. Shore
  Stylus for Prime screen steindid 6 2,287 10-22-2013, 02:06 AM
Last Post: Alberto Candel
  HP PRIME - Bode and Black plots - first attempt dg1969 0 1,028 10-20-2013, 01:32 PM
Last Post: dg1969
  Sending from graph to home or CAS screen Richard Berler 6 2,228 10-06-2013, 03:29 PM
Last Post: Tim Wessman
  HP48GX screen replacement Francisco Quiles 9 3,779 10-03-2013, 09:17 PM
Last Post: Francisco Quiles
  hp50g screen weird line Sok-khieng Chum Hun 2 1,569 09-10-2013, 08:11 AM
Last Post: Sok-khieng Chum Hun
  HP-11C "horse racing" version Peter Murphy (Livermore) 2 1,694 08-12-2013, 07:34 PM
Last Post: rpn fan
  HP-11C and complex numbers Antlab 5 2,144 06-28-2013, 08:59 AM
Last Post: Antlab
  HP 11C Batteries have lasted 22 years nink 3 1,395 06-23-2013, 06:51 PM
Last Post: Les Koller
  New screen on pictures of new Sharp EL-9950 Mic 4 2,018 06-10-2013, 10:40 AM
Last Post: Mic

Forum Jump: