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Bringing a Voyager (10c -- 16c) LCD back from the dead
09-10-2017, 06:25 AM (This post was last modified: 09-12-2017 09:28 PM by BarryT.)
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Bringing a Voyager (10c -- 16c) LCD back from the dead
Hi All,
This is my first post here... so my apologies in advance if this has been well documented somewhere, I can't seem to find anything on the topic though, so here goes... :-)

What I'm mainly really really wanting to know is... how the heck the LCD Displays work on these things? Does anyone have any information on how these things work? I'd love to know! :-)

Ok... now here's the "why".
I recently acquired a 15c, ( serial 2537A..., so 1985 ), that wasn't working... it's in pristine shape both inside and out, just nothing what so ever happens at power on. I carefully took it all apart, hoping it would be something as simple as a corroded\broken battery contact. Well... I found that corroded was correct. Not terribly, but far too much.

So, I grabbed my jewelers glass and started cleaning the board and the traces to get all the ugly green corrosion off. I even checked the board for power... it has good voltage, and when jumping across the individual buttons with the voltmeter, depressing the buttons shows flow. The traces on the board all 'appear' to be good, no broken circuits anywhere.

Afterwards, I tried again... and got a brief random batch of segments showing up, but then nothing. OK, now I know it has some life left... so onto removing the little heat stakes, ( wow, I sure would like to kick the person at HP who thought this was a good design... has the person never heard of screws? :-o ). These came off easily enough so I flipped the board over and found a good deal more corrosion, including under the LCD.

So, now I have a nice little LCD, nothing 'appears' to be wrong with it, so I set it aside. Next I take to cleaning the traces and board on this side. I even checked the resistor and, to the best I could with it on the board, I checked the capacitor, which I believe is also in working order.
After cleaning everything, and being totally befuddled by what traces on the PCB light up the various segments on the LCD, I decide to put the thing back together... and VOILA... there are more signs of life. I get some segments showing up, can input numbers, SIN and COS give me correct answers, etc. However, the thing is ghosting like crazy. The numbers are not whole, they are partial, and, despite the fact that the Multiply and Divide functions actually work, correctly, the self tests do absolutely nothing. :-( If Multiply and Divide work... I have no idea what would cause the two self-tests to not work.

Ok... so now I try one last time, in case there were parts that still didn't get cleaned, and now I get almost a completely alive display... still some segments out, on the very bottom, the "f" and a few others... AND, the self tests actually run now!!! Then after futzing with it, it goes dead again. :-o

OK, so that's where I'm at. I have this thing apart... it "appears" to want to live again, but the LCD wasn't displaying 100%. Might anyone have any advice on how to get this thing fully resuscitated?

Oh... also, does anyone know what the two teeny tiny springs are for? All they appear to do is connect the metal on the bezel to that on the back panel, and, that on the keyboard to the back panel. Grounding of some sort? To avoid static discharge perhaps?

Thanks in advance everyone.

Barry
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Bringing a Voyager (10c -- 16c) LCD back from the dead - BarryT - 09-10-2017 06:25 AM



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