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HP-41CV - doesn't power on

PostPosted: Mon Jan 23, 2017 12:51 am
by cappy2112
I've just received an HP-41CV and a few modules, for the cost of shipping.
The calculator is in very good condition- cosmetically, that is. I hope I can repair it.

I've installed a known good battery pack from another 41 that I use, but the HP-41 mentioned above does not turn on.
The contacts inside the calculator look very clean.

Would someone point me to some troubleshooting steps? I hope to narrow down which part(s) are bad, and decide to repair it
or sell it for parts.


Thanks

Tony

Re: HP-41CV - doesn't power on

PostPosted: Tue Nov 21, 2017 7:06 pm
by wgh52
Hello Tony and all HP-Fans,

I'm new to this forum and this is my first post. I am sooo glad to have found this site and forum as I do have the same problem with my HP-41CV: It stopped working today after working perfectly since ~ 1980 :shock:

The state of "play":
1. Switching "on" with a fresh battery pack yields a faint sizzling noise from the unit (which I never heard before!)
2. Hitting keys then sometimes produces a "beep"
3. In response to some key-strokes the display shows five high commas " ' ' ' ' ' " on the right side of the LCD display

All this seems to tell me, that there's still some life "under the (seemingly broken) surface" and it may be worthwhile to attempt repair.

Well, I have found a repair instruction post for the HP-41CX on this website which may be useful for the HP-41CV as well, but I'm not certain if the functional issue I face with it would be covered or mended by that major repair effort.

So, if anyone has had any good or bad experience with repair of an HP-41CV not powering on, I'd be extremely greateful for any answers and useful hints :!: :!:
IF I succeed in making my "beloved" Calculator work again, I plan to post a documented repair report with pictures in this forum.

I just cannot belive / accept that my HP-41 CV should be "gone" :roll:

Thanks!
Winfried

0001

Re: HP-41CV - doesn't power on

PostPosted: Tue Nov 21, 2017 9:54 pm
by cappy2112
Good luck getting a reply on this website.

Re: HP-41CV - doesn't power on

PostPosted: Tue Nov 21, 2017 10:58 pm
by rprosperi
wgh52 wrote:Hello Tony and all HP-Fans,
So, if anyone has had any good or bad experience with repair of an HP-41CV not powering on, I'd be extremely greateful for any answers and useful hints


The symptoms you describe could be due to loose posts (or the broken boss at the bottom of the well that holds the screw head for the 2 upper screws), though they also could be from other problems, but checking the posts, and repairing if needed, is the first step to take.

Some advice for disassembling/reassembling the 41:

1. Use a full size Philips screwdriver, not a jewelers size, hobby size, etc.

2. Turn the screws slowly, carefully and pay close attention to their progress into and out of the threaded posts/mounts.

3. Make sure the center bezel (between the upper/lower case halves) is oriented properly when you close the case, it only fits correctly one way.

4. When closing the case, hold it as tightly closed as you can, and again, screw them in slowly, watching progress until tight, DO NOT OVER TIGHTEN. This is a good time to have an extra set of hands, if a friend or patient wife/child is available.

It's annoying to repeat so much, but most posts/boss/screw damage is caused by people over-tightenting the screws.

Good luck with the repairs, and please share your results.