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HP Forum Archive 19

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LCD Failure?
Message #1 Posted by Bob Macklin on 30 Mar 2009, 9:12 p.m.

I am a retired EE. I purchased my HP 49SX in 1993. After I retired in 2K I only used it to balance my checking account. But a few years ago I started doing that on-line and the calculator sat unused on top of my VCR.

A few months ago I got it out to do some math that I dould not do with the Windows calculator. When I tried to turn it on I got no display. I figures it was the batteries so I put new ones in and it still did not work.

Today in reading the manual it says the if you don;r get a display when you turn it on to hod the ON button down while repeatedly pressin the "+" key.

I tried this for an extended period. No sign of life in the display.

Do these LCD displays have a failure mode due to age or non-use?

Bob Macklin Seattle, Wa.

      
Re: LCD Failure?
Message #2 Posted by Allen on 30 Mar 2009, 9:16 p.m.,
in response to message #1 by Bob Macklin

the 48sx has a pretty high failure rate on the LCD. You can also try a soft reset by pressing ON+A+F at the same time, or by inserting a paperclip into the reset hole under the top left foot. If you do get it to come on ( or not, I suppose) you can also try pressing firmly with your thumb above the B and C keys while toggling power this applies extra pressure to the LCD display connector. Others?

            
Re: LCD Failure?
Message #3 Posted by Bob Macklin on 30 Mar 2009, 10:34 p.m.,
in response to message #2 by Allen

The LCD is not dead! Pressing above the B & C keys while pressing th power button made it come to life! But I have to press ther to turn it off also. It seems that any operation involving the "ON" button requires the pressure above the B & C keys.

Once on it seems to function normally. Since I have not used it in many years I now will have to get reaquited with it!

Thanks for the clue!

Bob Macklin Seattle, Wa.

      
Re: LCD Failure?
Message #4 Posted by DaveJ on 30 Mar 2009, 9:36 p.m.,
in response to message #1 by Bob Macklin

Quote:
I am a retired EE. I purchased my HP 49SX in 1993. After I retired in 2K I only used it to balance my checking account. But a few years ago I started doing that on-line and the calculator sat unused on top of my VCR.

That might be the cause of the failure.
The top of a VCR get get fairly warm.
Sit a calculator there for several years and it's probably not going to like it too much.

Dave.

            
Re: LCD Failure?
Message #5 Posted by Garth Wilson on 31 Mar 2009, 12:46 a.m.,
in response to message #4 by DaveJ

Heat and humidity (especially the combination) kill LCDs, but not particularly by making them just plain quit, but rather by darkening the background slowly until it's useless. UV isn't good for them either. I had a cheapie LCD clock stuck on the dashboard of a car (where it was always shaded) for 12 years though, and in spite of all the heat, it remained fine.


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