Post Reply 
Illuminating the HP49G LCD display?
01-07-2022, 07:16 AM
Post: #1
Illuminating the HP49G LCD display?
I tested my 49G the other day, and it had developed keyboarditis, i e to start it up you have to push hard on the bezel above the softkeys in order for it to wake up.

So: I'll have to open it up and fix the kbd connector.

So I thought I might try to add some LEDs arranged near the display to improve readability of the rather dim LCD.

Has anybody else tried this?
What LEDs could you use? Where should you connect the LED to minimize the strain on the electronics and so it would only light up when the calculator is on?
Find all posts by this user
Quote this message in a reply
01-27-2022, 09:54 PM (This post was last modified: 01-27-2022 09:57 PM by Vtile.)
Post: #2
RE: Illuminating the HP49G LCD display?
(01-07-2022 07:16 AM)n3mmr Wrote:  I tested my 49G the other day, and it had developed keyboarditis, i e to start it up you have to push hard on the bezel above the softkeys in order for it to wake up.

So: I'll have to open it up and fix the kbd connector.

So I thought I might try to add some LEDs arranged near the display to improve readability of the rather dim LCD.

Has anybody else tried this?
What LEDs could you use? Where should you connect the LED to minimize the strain on the electronics and so it would only light up when the calculator is on?
I suppose you have opened it already, anyway if the internals are similar than in 50g there is no much room for leds. Only point where the leds could work is an edge of the LCD glass edge, but the illumination effect is rather poor and in 50g only SMD devices fit physically IIRC. SD card and IIRC serial port did have place to make software controller FET switch for leds. One option would be removing the entire back coating of LCD and replacing it with something illumination friendly diffusor, but I never did go that far on re-engineering.
Find all posts by this user
Quote this message in a reply
01-27-2022, 10:11 PM
Post: #3
RE: Illuminating the HP49G LCD display?
See this topic: https://www.hpmuseum.org/forum/archive/i...d-614.html

http://WilsonMinesCo.com (Lots of HP-41 links at the bottom of the links page, http://wilsonminesco.com/links.html )
Visit this user's website Find all posts by this user
Quote this message in a reply
01-28-2022, 02:36 PM
Post: #4
RE: Illuminating the HP49G LCD display?
Back in the late '90s when I got my 49G, I found that the readability was improved tremendously by simply removing the plastic lens covering the LCD. This leaves the LCD sitting out in the open, much like on the 48. I grabbed a spare 5.25" floppy disk and cut a new bezel from the outer jacket and stuck it on to make it at least sort of nice looking.

https://i.imgur.com/HbMBTuz.jpg

Looks pretty good. The keyboard still sucks though. Smile
Visit this user's website Find all posts by this user
Quote this message in a reply
01-28-2022, 03:28 PM
Post: #5
RE: Illuminating the HP49G LCD display?
(01-28-2022 02:36 PM)Dave Britten Wrote:  Back in the late '90s when I got my 49G, I found that the readability was improved tremendously by simply removing the plastic lens covering the LCD. This leaves the LCD sitting out in the open, much like on the 48. I grabbed a spare 5.25" floppy disk and cut a new bezel from the outer jacket and stuck it on to make it at least sort of nice looking.

https://i.imgur.com/HbMBTuz.jpg

Looks pretty good. The keyboard still sucks though. :)

What really sucks is that 'ALG' on the upper right... :P

Greetings,
    Massimo

-+×÷ ↔ left is right and right is wrong
Visit this user's website Find all posts by this user
Quote this message in a reply
01-28-2022, 03:40 PM
Post: #6
RE: Illuminating the HP49G LCD display?
(01-28-2022 03:28 PM)Massimo Gnerucci Wrote:  
(01-28-2022 02:36 PM)Dave Britten Wrote:  Back in the late '90s when I got my 49G, I found that the readability was improved tremendously by simply removing the plastic lens covering the LCD. This leaves the LCD sitting out in the open, much like on the 48. I grabbed a spare 5.25" floppy disk and cut a new bezel from the outer jacket and stuck it on to make it at least sort of nice looking.

https://i.imgur.com/HbMBTuz.jpg

Looks pretty good. The keyboard still sucks though. Smile

What really sucks is that 'ALG' on the upper right... Tongue

Yeah, I only popped batteries in to take this picture. I wasn't going to use the keyboard any more than necessary. Big Grin
Visit this user's website Find all posts by this user
Quote this message in a reply
01-28-2022, 06:30 PM
Post: #7
RE: Illuminating the HP49G LCD display?
Sorry, leaving it in ALG mode guarantees you will use the keyboard more. IIRC, even turning a machine off takes more keystrokes in ALG mode... Smile

--Bob Prosperi
Find all posts by this user
Quote this message in a reply
01-29-2022, 05:54 AM
Post: #8
RE: Illuminating the HP49G LCD display?
(01-28-2022 06:30 PM)rprosperi Wrote:  Sorry, leaving it in ALG mode guarantees you will use the keyboard more. IIRC, even turning a machine off takes more keystrokes in ALG mode... Smile
what if he takes batteries out without keystrokes at all? Smile
Find all posts by this user
Quote this message in a reply
Post Reply 




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