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hp 48G/GX unavoidable DEATH !!
04-03-2018, 06:11 PM
Post: #1
hp 48G/GX unavoidable DEATH !!
i have just read a comment somewhere on YouTube saying that all hp48G/X calculators are on unavoidable functionality countdown as the LCD technology used for their displays was not perfect at the time and those displays are about to become nonfunctional and die very soon even if the unit has seen little or no use it is just a matter of time before all the units will go blind.
hp 48 users what do you think about that ???
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04-03-2018, 07:01 PM
Post: #2
RE: hp 48G/GX unavoidable DEATH !!
Unfortunately the hp 48 users are also on unavoidable functionality countdown and are about to become nonfunctional and die sooner or later even if they have seen little or no use. It is just a matter of time. Wink

For LCD displays, currently the ones that are facing mass extinction are the early yellow ones, such as the displays used in the Sharp EL-5100 or PC-1211 from the late 70's/early 80's which are gradually becoming black.

[Image: Sharp%20PC%201211.jpg]

Someday the 48 LCDs will also die but I think we still have time to enjoy using these calculators.
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04-03-2018, 07:26 PM
Post: #3
RE: hp 48G/GX unavoidable DEATH !!
(04-03-2018 07:01 PM)Didier Lachieze Wrote:  Unfortunately the hp 48 users are also on unavoidable functionality countdown and are about to become nonfunctional and die sooner or later even if they have seen little or no use. It is just a matter of time. Wink

For LCD displays, currently the ones that are facing mass extinction are the early yellow ones, such as the displays used in the Sharp EL-5100 or PC-1211 from the late 70's/early 80's which are gradually becoming black.

[Image: Sharp%20PC%201211.jpg]

Someday the 48 LCDs will also die but I think we still have time to enjoy using these calculators.

Interesting, so why these units (even the older 48S/X) are still available on eBay?
why would anyone wants to spends +200$ for a calculator that soon will turn into a decoration object without any functional use?
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04-03-2018, 07:35 PM
Post: #4
RE: hp 48G/GX unavoidable DEATH !!
(04-03-2018 07:26 PM)zx_spectrum Wrote:  Interesting, so why these units (even the older 48S/X) are still available on eBay?
why would anyone wants to spends +200$ for a calculator that soon will turn into a decoration object without any functional use?

I never spent so much for a vintage calculator, but I know there are out there many people that are spending +1000$ for a phone that soon will turn into a decoration object without any functional use, while my HP-35 from 1972 or my 41C from 1981 will continue to work for many years Wink
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04-03-2018, 07:52 PM
Post: #5
RE: hp 48G/GX unavoidable DEATH !!
I never spent so much for a vintage calculator, but I know there are out there many people that are spending +1000$ for a phone that soon will turn into a decoration object without any functional use, while my HP-35 from 1972 or my 41C from 1981 will continue to work for many years Wink
[/quote]

do you recommend any alternative RPN calculator ?
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04-03-2018, 11:00 PM
Post: #6
RE: hp 48G/GX unavoidable DEATH !!
(04-03-2018 07:52 PM)zx_spectrum Wrote:  do you recommend any alternative RPN calculator?
With a Curta, you don't need to fear display bleeding in the way LCDs are prone to;-)

-- Ray
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04-03-2018, 11:18 PM
Post: #7
RE: hp 48G/GX unavoidable DEATH !!
(04-03-2018 07:01 PM)Didier Lachieze Wrote:  For LCD displays, currently the ones that are facing mass extinction are the early yellow ones, such as the displays used in the Sharp EL-5100 or PC-1211 from the late 70's/early 80's which are gradually becoming black.

Well, I happen to own a Sharp PC-1211 in that condition (in fact a pic of it would very accurately match the one you posted) but it's still perfectly workable.
The blackening affects only the part of the display external to the dot-matrix alphanumeric characters which still remain perfectly visible when the machine is turned on.

It's certainly a cosmetic nuissance but it does not render the calculator utterly unusable, it works Ok regardless.

AND (a very important AND) this has only happened to one of my SHARP PC-1211, which already came in that condition when I got it. The rest of my yellow-LCD PC-1211 are still perfectly fine with no blackening at all despite being some 38 years old, give or take a year. The grey-LCD ones (PC-1212) are all perfectly Ok, never seen one with a blackened display.

V.
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04-03-2018, 11:20 PM
Post: #8
RE: hp 48G/GX unavoidable DEATH !!
(04-03-2018 07:26 PM)zx_spectrum Wrote:  Interesting, so why these units (even the older 48S/X) are still available on eBay?
why would anyone wants to spends +200$ for a calculator that soon will turn into a decoration object without any functional use?
What do you mean with "soon"? During the next week, year, decade?
If I got Didier correctly, he may have wanted to say that nothing is made for ever, be it man or machine.

I'd say that most of the calcs which are still working after more than a decade of usage are over-engineered;-)

Which was especially true for many of the older HP calcs, although each series had at least one specific weak point.

-- Ray
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04-04-2018, 02:21 AM
Post: #9
RE: hp 48G/GX unavoidable DEATH !!
(04-03-2018 11:18 PM)Valentin Albillo Wrote:  The blackening affects only the part of the display external to the dot-matrix alphanumeric characters which still remain perfectly visible when the machine is turned on.

It's certainly a cosmetic nuissance but it does not render the calculator utterly unusable, it works Ok regardless.

I can't say how this evolves overtime, but I've seen a lot of units being sold with such defect, which can affect also the alphanumeric characters :

[Image: PC1211-4.jpg]

Storage conditions (temperature, humidity, pression, and variation of these) may play a role in how the defect appears and evolves. As the blackening starts on the edges and seems to move to the center of the screen this may be due to the sealing of the display glass panels degrading overtime. The Sharp grey LCDs are less impacted than the yellow ones but they are not totally immune.

You can see a collection of units pictures with more or less bad LCDs here and here, including a Sharp EL-5100S with a defective grey LCD.
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04-04-2018, 02:11 PM (This post was last modified: 04-04-2018 02:12 PM by zx_spectrum.)
Post: #10
RE: hp 48G/GX unavoidable DEATH !!
(04-03-2018 11:20 PM)Raymond Del Tondo Wrote:  
(04-03-2018 07:26 PM)zx_spectrum Wrote:  Interesting, so why these units (even the older 48S/X) are still available on eBay?
why would anyone wants to spends +200$ for a calculator that soon will turn into a decoration object without any functional use?
What do you mean with "soon"? During the next week, year, decade?
If I got Didier correctly, he may have wanted to say that nothing is made for ever, be it man or machine.

I'd say that most of the calcs which are still working after more than a decade of usage are over-engineered;-)

Which was especially true for many of the older HP calcs, although each series had at least one specific weak point.

well but if the calculator was built in mid 90's so if i buy it today from eBay it already would be over 25 years old and thus it may not remain in my service more than 2-5 years. so spending hundreds of dollars for such unit doesn't seem rational to me.
again, the LCD-death soon is not my claim, i just read that somewhere and want to check the validity of this claim with hp 48G users
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04-05-2018, 01:53 AM
Post: #11
RE: hp 48G/GX unavoidable DEATH !!
Not sure I believe this is a problem. Of all the HP48s I have owned or used the only display problem not related to an impact was an early SX which was a factory defect which HP fixed for free. This was a known problem with early SXs. I currently own an SX and two GXs and all their displays are perfect. If these were failing regularly we would be seeing all sorts of posts about it here.

On the other hand the connector between the boards is a known weakness and much more likely to cause you problems. While fixable it does require that you open the case which is not easy.
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04-05-2018, 09:35 AM
Post: #12
RE: hp 48G/GX unavoidable DEATH !!
For those interested in the technical history of LCDs:
"Liquid Gold - The Story of Liquid Crystal Displays and the Creation of an Industry" by Joseph A Castellano.
A very technical but interesting read.

As the blackening effect usually starts from the edges, I assume that the seal between the two glass plates becomes porous over time. Then oxygen can interact with the liquid or the liquid "dries out". Maybe an early resealing of the edges with epoxy or something similar could help?
Any LCD manufacturers / experts here?

Martin
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04-05-2018, 09:47 AM
Post: #13
RE: hp 48G/GX unavoidable DEATH !!
(04-03-2018 11:00 PM)Raymond Del Tondo Wrote:  
(04-03-2018 07:52 PM)zx_spectrum Wrote:  do you recommend any alternative RPN calculator?
With a Curta, you don't need to fear display bleeding in the way LCDs are prone to;-)

Yeah but I have a heluva hard time finding batteries for the Curta! Big Grin

Tom L

I never knew my mother was such an animal lover. When the doctor told her the rabbit died, she went into shock!
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04-05-2018, 09:57 AM
Post: #14
RE: hp 48G/GX unavoidable DEATH !!
(04-05-2018 09:35 AM)Martin Hepperle Wrote:  As the blackening effect usually starts from the edges, I assume that the seal between the two glass plates becomes porous over time. Then oxygen can interact with the liquid or the liquid "dries out". Maybe an early resealing of the edges with epoxy or something similar could help?
Any LCD manufacturers / experts here?

Martin

I'd guess this is what is happening too,
I went looking at some last night on ebay, there are some examples of this era of calc/pocket computer with perfectly good LCD, and then another of the same model with a bleeding one (not caused by physical damage)
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04-05-2018, 03:13 PM
Post: #15
RE: hp 48G/GX unavoidable DEATH !!
This thread reminds me of an earlier post by hp41cx

http://www.hpmuseum.org/forum/thread-9429.html

If you follow the link he provides in the first post you'll see an article on repairing a multimeter display that has developed a large dark spot in the middle. This may be a different failure mechanism than edge-bleed inward, but it might be worth trying.

If a 48 series display ever does go bad, it can be replaced by one from a more recent stretch pioneer model, giving you a few more years of happy computing!

~Mark
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04-05-2018, 04:24 PM
Post: #16
RE: hp 48G/GX unavoidable DEATH !!
My Dad's HP-15C is 31 years old and the LCD display has 0 issues.
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04-05-2018, 04:26 PM
Post: #17
RE: hp 48G/GX unavoidable DEATH !!
Interesting. I posted a while back about how I had to have the LCD on my HP-41C replaced after less than a year due to a corner of the display turning black. Fortunately it has never recurred.
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04-06-2018, 07:32 AM (This post was last modified: 04-06-2018 07:34 AM by ijabbott.)
Post: #18
RE: hp 48G/GX unavoidable DEATH !!
(04-05-2018 03:13 PM)mfleming Wrote:  This thread reminds me of an earlier post by hp41cx

http://www.hpmuseum.org/forum/thread-9429.html

If you follow the link he provides in the first post you'll see an article on repairing a multimeter display that has developed a large dark spot in the middle. This may be a different failure mechanism than edge-bleed inward, but it might be worth trying.

That looks like a fix for a problem with the reflective backing rather than a problem with the liquid crystal glass and polarizer sandwich.

Also, that looks like an el cheapo multimeter. Hopefully, the likes of Fluke use better quality displays!
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04-07-2018, 07:24 AM
Post: #19
RE: hp 48G/GX unavoidable DEATH !!
(04-05-2018 04:24 PM)Carsen Wrote:  My Dad's HP-15C is 31 years old and the LCD display has 0 issues.

I reckon that's pot luck.

I recently inherited an HP-16C that did have screen bleed but I was able to replace the LCD with one from a donor 15C of greater age and it's still in perfect condition now.
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04-07-2018, 07:49 PM
Post: #20
RE: hp 48G/GX unavoidable DEATH !!
Perhaps someone has/or can study the interface between the dispaly driver circuits and the HP48 series LCD and start work towards replacing it with a more modern display.

Granted not simple, but it would be a shame for these machines to become 'uncommunicative!'

TomC
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