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I had a HP-42s sitting around for a year or two that I didn't use. I decided I needed it again and put fresh batteries in it. I couldn't get it to power up. The old batteries didn't leak. I had the same thing happen with my old HP-41CV from college, but I just figured it was age. Now I'm thinking it's a conspiracy ;-) since it happened again. Is there anything special I need to do to get it to power up when it hasn't been used in a while?

Of course you may have checked, but reverify polarity of batteries in slot for correctness, and check voltage at the calculator battery terminals for about 4.8v or so that should be there with 3 new ones. Clean contacts/batteries with an eraser or other light abrasive if needed. Hold down the on button firmly for 10 seconds or so and try numerous times, I have had that work on both series after batteries have been out awhile. Other than that the sharp hand rap methods begin to come in to play before dissassembly which would not be fun. Good luck

Frank counsel is OK, just also try a full reset (press ON, SIGMA and XEQ in order, keeping the previous keys pressed; then release in inverse order).

With the batteries OUT, you may also shortcircuit the battery terminals, to discharge capacitors. This will also clear all memory.

CAUTION: If you clean contacts with an eraser, be very careful not to let debries inside: you will not be able to clean them later.

I had a HP41 which would not "turn on" with a new set of batteries after it was left in the closet for a couple of years (without batteries).

Turning it on with all sorts of previously prescibed methods had no effect on it. But, when the SHIFT BEEP key sequence was executed the calulator BEEPed! Although there was no sign of life from the display, I wrote a brief program to execute the various TONEs and it worked!

Conclusion (if I am not mistaken), the LCD goes bad if the calulator is not switched on occasionally to exercise the liquid crystals in the display.

My 71B had the same fate, though I was not able to revive it :(

Regards

I cleaned the terminals with an eraser and then shorted them out. I think probably that shorting them out probably did it since the terminals looked clean. Now, if I only hadn't of thrown my 41 in the can. I guess that's a mortal sin on this board...

If you feel bad about throwing away a potentially good HP41, I throw away a mint condition HP41CV. I kept it for a few years after I bought my HP42. Even though it worked just fine, I saw no use in keeping it after the 42. Out it went!

Bill

PS This is before I discovered the Internet.

I thought I threw it out. When I got home tonight, I checked and I still had my 41CV. I shorted out the calculator, and put the same brand new N cell batteries that wouldn't power it up before, and voila, it now works. I do like the 42s better, but the 41CV brings back all those memories from college.

another trick that has worked for me is to bleed the capacitor of charge then reinstall new batteries

1. take old batteries out 2. hit the on key many times (about 15 or so)

(apperently this removes any charge the capacitor has left) 3. put new batteries in 4. turn on

note: i saw this method in the comp.sys.hp48 newsgroup to fix a hp48 problem but it worked with the 42s and probably will work for the 41

[there are no guarantees however]

I didn't throw mine away, but I gave away my HP41CV and printer and card reader, and cards, and nicad pack, and 2 x chargers to a person I saw carrying around an HP41.

I suppose it's better than throwing them out, and I hope to this day that the person found a use for them.

steve; reminds me of a tv program my folks watched when i was very young. each week some guy would knock on a different persons door and just hand them a million bucks.

Throwing out manuals is almost as bad! I did this for my 41CV, and I kick myself every day! What the heck was I thinking???????

Todd