HP48GX how many years will it last?



#8

I have a question
I do have 4 GX, 2 used everyday.
The other 2 are well packed, but without batteries.
I would like to know what do I have to do to mantain this 2 new units for years without use.
Do I have to put sometimes the batteries?
Or never put the batteries, and the capacitor?
Thanks.


#9

Hi, Karl;

although this is not a direct answer to your question, I'd consider those packed HP42S found last year. How long had they been stored and under which conditions?

If HP is still HP (I doubt), I'd tell you they'd be the best source of information regarding your question. But I'd not be surprised if the attendant asks you back what sort of mainframe is that...

I'd keep them in the box the way they are now. And see what happens when you finally insert the batteries and turn it on. Would you let your grand-children have the honor? Kidding...

Cheers.

Luiz (Brazil)

#10

I would power them up with batteries every couple of years just to charge the capacitors (just in case).

The weak spot for the 48G series is the compression pads just below the LCD screen. When these soften up with age (and nothing can slow this ageing process), the keyboards fail, especially the ON key. Many people believe their keyboards may suffer from dirt and wash their keyboards in the belief that they are removing dirt or other mat'l from the keypad, when in reality, they are probably just adding moisture to this pad and restoring its pressure and therefore fixing their keyboards. That is my belief, for what its worth.

I plan to experiment with a syringe and a chemical to fix/expand seals in automatic transmissions (balloons our rubber to 1.5-3x upon contact. It is supposed to fix seals, but I am hoping to have it restore the compressive force of the pad to its old self. I prefer this approach to removing the faceplate and adding more material as any work on the faceplate becomes ugly. I have yet tried this yet, but feel it holds promise.

That is what I feel is the Archilles heal of the 48g series.


#11

WOW! so that's what was wrong with this 48S I found in the trash can. When I found it, it had sticky residue on it so I washed it in an ultrasonic bath of warm d/i water. After drying it for several days it still didn't work but it looked so good I didn't have the heart to just throw it away.

After reading the post about the compression pad beneath the LCD I put batteries back in it and squeezed the area below the LCD and above the soft-keys between my thumb and forefinger. What excitement! When I pressed the on key it powered up. The 48s lives!

Now the question is how do I permanantly restore the pad so I don't have to keep squeezing the calc to use it?

Andy

#12

The electronics won't deteriorate, but I'm not at all sure about the display. Nor do I know whether regular powering will do any good.

I think one has to know about lcd technology to answer your question. Not me. Sorry.


#13

If the calculator has any aluminum electrolytic capacitors (I can't say if it doe or doesn't.) it should be briefly powered up once every three months or so to keep the dielectric formed. If it has tantalum electrolytic capacitors this is unnecessary.

Store in a place that's cool and not too humid.

#14

"The electronics won't deteriorate"

Not completely true, electrolytic capacitors will deteriorate over time, perhaps 10 years before they start showing problems. Occasional powering up may help but won't avoid the problem completely. Solder joints can also go 'dry' and loose contact, the only cure I know is to re-heat them while adding a touch of new solder.

Various plastics and foams will deteriorate over time from UV and the chemicals in air.

I'm not sure about the LCD - when first introduced LCD's had a yellow filter as UV? could damage them. Contrast on some LCD's seems to be lost with age but they rarely fail. LED displays were thought to be much more reliable - the displays may be but the high(ish) current display drivers can suffer.

Keep them wrapped up in a cool and dry place and power up every 6 months.


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