A sad story of HP calculators

[stephenmendes]

Hello Everybody,

I started with the 48SX back in the early 90's (my pride and joy at University).... and then I got the 48GX ..... and then the 49G ..... then the 49G+ ..... along the way I picked up Sparcom libraries and expansion memory for the ports of the 48

One by one all the screens turned black ..... I made a video and put it on Youtube... but nobody came up with a solution.

However, I am not completely destitute ..... as I have two 50G calculators that I bought while they were still selling new on Amazon ..... over the years I have grown to love these (even though it took me a while to recover from the loss of my 48's )

The two most important features that define why I will never want any other brand of calculator are the RPN entry ..... and the user keyboard, where I have keys programmed to do all the original functions that had a dedicated key (switching the display between Polar and Rectangular being the most used of those)

I have lost other monochrome LCD devices also..... must be the temperature and humidity of the tropics ?.... has anybody else experienced this ?

and yet there are screens that have survived..... I have a Yamaha keyboard from the 80's (being the oldest example)

I never had the heart to throw out the hp calculators ..... because they were all working perfectly before the screens went black...... usually an oval patch that just expands and expands outward until nothing can be seen

Any hope ? ..... Anybody want them ?

Best Wishes,
Stephen Mendes

[Gerson W. Barbosa]

(04-27-2020 08:29 PM)stephenmendes Wrote:  I have lost other monochrome LCD devices also..... must be the temperature and humidity of the tropics ?.... has anybody else experienced this ?

Same here, about 200 km southwards from the Tropic of Capricorn, rather dank city:

https://www.hpmuseum.org/forum/post-71768.html#pid71768

Currently also another unusable HP-49G. Really annoying.

[Dave Frederickson]

Here's a demonstration of how to repair the screen.



It does look labor intensive and you need a replacement for the screen backing.

But once you've the calculator apart you might as well replace the screen with the black high-contrast version from a donor 39G. See these posts.
https://www.hpmuseum.org/cgi-sys/cgiwrap...002#108107
https://www.hpmuseum.org/cgi-sys/cgiwrap...ead=251848

Dave

[stephenmendes]

(04-27-2020 10:11 PM)Dave Frederickson Wrote:  Here's a demonstration of how to repair the screen.



It does look labor intensive and you need a replacement for the screen backing.

But once you've the calculator apart you might as well replace the screen with the black high-contrast version from a donor 39G. See these posts.
https://www.hpmuseum.org/cgi-sys/cgiwrap...002#108107
https://www.hpmuseum.org/cgi-sys/cgiwrap...ead=251848

Dave

Thanks Dave..... I may attempt this ..... but appreciate the encouragement and your post

[AndiGer]

(04-27-2020 10:11 PM)Dave Frederickson Wrote:  Here's a demonstration of how to repair the screen.
(...)
Dave

Dave,
The link you embedded isn't the youtube video but the link to the image you attached in your answer in thread named "How to export HP-41 programs to PC"

Could you correct that one in this thread please?

[Garth Wilson]

I read approximately 35 years ago that the heat-and-humidity combination is a real killer for LCDs. Here in Southern California where we live, it can get pretty hot for short times every year, but the humidity is not bad. The only ruined LCD I've seen was one that was stored in an attic for a long time. None of the LCDs in our family has gone bad (and that's a lot of LCDs).

[Jonathan Busby]

(04-27-2020 10:11 PM)Dave Frederickson Wrote:  Here's a demonstration of how to repair the screen.



It does look labor intensive and you need a replacement for the screen backing.

But once you've the calculator apart you might as well replace the screen with the black high-contrast version from a donor 39G. See these posts.
https://www.hpmuseum.org/cgi-sys/cgiwrap...002#108107
https://www.hpmuseum.org/cgi-sys/cgiwrap...ead=251848

Dave

When I try to play the video, I get the error :

Code:

An error occurred. Please try again later.
(Playback ID: 97fRfxc-oaw89Vqb)

Regards,

Jonathan

[Dave Frederickson]

Sorry folks, here's the correct link.

[Jonathan Busby]

(04-28-2020 05:50 PM)Dave Frederickson Wrote:  Sorry folks, here's the correct link.

Thanks!

Regards,

Jonathan

[BillBee]

I would look at using a piece of Mylar (assuming you perform the surgery without losing any digits).

-B