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Dying HP41 Displays
10-12-2015, 03:47 PM (This post was last modified: 10-12-2015 03:51 PM by Harald.)
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Dying HP41 Displays
I have 4 HP41s. Three of which have a display problem now.

No. 1:
Has excessive current draw and will only start on almost depleted batteries. I got it off ebay and all was fine until I replaced the batteries. It wouldn't start anymore and I fiddled with it until it did. Only to find the batteries were almost dead again. Took me a while to figure out what was going on. Initially I thought it was the CPU board, but it tunrned out the problem is the display board.

No. 2:
I bought for parts (hoping the display was good) and for the very nice tall key keyboard. But after cleaning it of all its corrosion, the only thing that didn't work was - you guessed it - the display. It displays something that looks like @ signs all the time. Sometimes I can get it back to life by repeatedly resetting the machine and removing and inserting the batteries several times. Once it works it is fine. But removing and replacing the battery puts you back into the same trouble.

No. 3:
Has just lost a decimal point. On closer inspection there are also segments missing from the last two digits. So it will only display exponents partially - so not really usable at all.

No. 4:
Probably best not to touch this. I don't want any more display failures...

Any idea what the issue is? Especially with No.3. There is no way it could be a bad connection of the CPU board to keyboard, could it? If Segments are missing I guess it can only be the zebra connector, right? Maybe that is due to a climate change. I just took it from home to work, where it is much drier (we are at about 15% rel. humidity here now) than at home.

Chris Chung - Hurry up with your NP41! I need a backup plan Smile
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Messages In This Thread
Dying HP41 Displays - Harald - 10-12-2015 03:47 PM
RE: Dying HP41 Displays - Geoff Quickfall - 10-12-2015, 04:32 PM
RE: Dying HP41 Displays - Geoff Quickfall - 10-12-2015, 06:40 PM
RE: Dying HP41 Displays - Harald - 10-12-2015, 10:20 PM
RE: Dying HP41 Displays - Geoff Quickfall - 10-13-2015, 05:55 AM
RE: Dying HP41 Displays - Harald - 10-13-2015, 07:53 AM

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