HP-41CV - doesn't power on

Everything about 41C 41CV and 41CX Hardware

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

Postby cappy2112 » Tue Nov 28, 2017 7:35 pm

wgh52 wrote:OK folks,

Part 1 of my HP41CV repair report.

Disassembly


After removing the 4 rubber feet 4 screws were loosened, the back cover lifted. and coveres removed:

Image

Looking into the void between the upper and lower PCB it became obvious, that there only was partial contact between them by the flexible contact rolls (no image of that, hard to take a picture, sorry), so I removed the the upper PCB and the flexible connection roll(s):

Image

This gives access to all connection pads and also (sadly) obviated that the lower right fastening pole is badly broken (i.e. horizontally and that broken off part broke into two pieces a few moments later).

Contacts cleansing

Staying cool about that broken pole I've now first proceeded by cleaning all contactpoints with a mild nail lacqer solvent (had good experience with that in other gold on gold contact problem cases).

Image

This is where I stand now. Next step is the repair of the mounting pole and then reassembly of the unit to see if we have progress or success already.

What I actually have at hand is an "Ethyl-2-Cyanacrylat" glue which I hope will do the job as it helped well in other plastic glueing cases which needed to provide mechanical stability... Any more hint, warning and/or advice would be much appreciated!

Kind greetings,
Winfried

0005


Thanks for this info.
What happened to the images?
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Re: HP-41CV - doesn't power on

Postby wgh52 » Tue Nov 28, 2017 7:39 pm

Still could not hold my hands still - just HAD TO check :twisted: if looking for a longer screw will mean repair success! So I assembled the thing as is (missing the one screw) and ...

TaaaDaaaaaa!!!! This god damned bugger lives!

Image

...just needs some encouraging pressure on the lower left corner (where the screw is currently missing) and it works!

So, this simple,longer screw shall not be a road block to final success! There will be a solution!

To be continued...

:D Cheers,
Winfried

PS: I can already say now: Never give up easily on an HP!

0007
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Re: HP-41CV - doesn't power on

Postby wgh52 » Tue Nov 28, 2017 7:48 pm

Hey "cappy2112",

cappy2112 wrote:...What happened to the images?

Ooooopppsss??? The images are all PNGs and display well on my IE and Firefox browsers - even when quoted in your reply :? No idea why you don't seem to see them, they're posted on a picture hosting service site in Europe.

Regards,
Winfried

0008
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Re: HP-41CV - doesn't power on

Postby cappy2112 » Tue Nov 28, 2017 8:13 pm

wgh52 wrote:Hey "cappy2112",

cappy2112 wrote:...What happened to the images?

Ooooopppsss??? The images are all PNGs and display well on my IE and Firefox browsers - even when quoted in your reply :? No idea why you don't seem to see them, they're posted on a picture hosting service site in Europe.

Regards,
Winfried

0008


Why do they need to be hosted anywhere?
Why not just attach them to these posts?
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Re: HP-41CV - doesn't power on

Postby wgh52 » Tue Nov 28, 2017 8:22 pm

Because I may use them otherwise as well.
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Re: HP-41CV - doesn't power on

Postby wgh52 » Tue Nov 28, 2017 8:35 pm

OK. Let me pracitce ;)

1 Dissassemble 2.PNG
Disassemble 1


1 Dissassemble 3c.PNG
Disassemble 2


2 Cleansing.png
Cleansing the connections/connectore


Tedious - 3 Pictures limit :cry:

Continued next Post...

Winfried

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

Postby wgh52 » Tue Nov 28, 2017 8:39 pm

4 cracked Posts.PNG
Destroyed Post parts


5 Screw length 1.PNG
Identify max. screw length
5 Screw length 1.PNG (35.27 KiB) Viewed 854 times


6 Test 1.PNG
It works with Thumb pressure without missing screw


Hope this is visible for everyone now.

Cheers,
Winfried

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

Postby cappy2112 » Tue Nov 28, 2017 9:00 pm

wgh52 wrote:
4 cracked Posts.PNG


5 Screw length 1.PNG


6 Test 1.PNG


Hope this is visible for everyone now.

Cheers,
Winfried

0010


These ar evisible to me.
Not sure why the website is filtering the linked ones.
That's one for the admin
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Re: HP-41CV - doesn't power on

Postby rprosperi » Tue Nov 28, 2017 10:48 pm

Winfried:

For contact cleaning, I recommend DeOxit brand contact cleaners (Red for cleaning, Gold for preserving/long-term). Acetone (your nail polish remover) can damage all plastics and even some board materials. I've read it can also damage leads on PC boards, but that seems like an exaggeration to me, maybe others can confirm or refute that.

Most folks have reported poor results gluing vintage calculator parts using various types of superglue/crazy glue/other brands (all forms of cyanoacrylate).

2-part epoxies seem to have the best results, I personally have found JB-Weld "PlasticWeld" excellent. There are many flavors of even just this brand/type, with various color (black, white, putty/beige) and speed (of drying) options. For general purpose use, I typically use quick-setting, translucent yellow as it matches most places. For internal repairs, color likely doesn't matter.

It appears what's left of the post would be hard to glue back together, so it will have to be replaced.

One source of 41 repair parts is The Calculator Store, an online (excellent) website/webstore in Spain. Here is the 41 parts page:

https://www.thecalculatorstore.com/epages/eb9376.sf/en_US/?ObjectPath=/Shops/eb9376/Categories/The_HP41_corner

The parts from here are not cheap, and add shipping from Europe (assuming you're in US) and it's worse, however they have a good reputation and many folks have provided positive feedback about their parts and support. I have not used them myself, but I would not hesitate.

As a last resort, I can recommend an experienced repair service if you'd like, but hopefully you can get through the repair yourself.

Continued good luck!
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Re: HP-41CV - doesn't power on

Postby Garth » Wed Nov 29, 2017 12:05 am

Your pictures have always shown up correctly for me. No problem here. I have firefox running under Ubuntu 14.04 Linux and the Gnome Flashback Compiz GUI.
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