HP-41 keyboard issue - help from the hardware gurus here



#8

My HP-41CV (fullnut) turned into an HP-41CL has an issue with the minus (-) key: I need to press it rather hard for it to register.

Now before I open it up and start some kind of a hit & miss adventure, I thought I'd ask the gurus of this board for a virtual hand. How exactly do I go about fixing/cleaning out this issue (baby steps please, I'm a software guy).


#9

Hello Geir,

Take apart the calc with the usual anti static precautions.

Obtain a small tube of DeOxit gold. Find the pinhole on the circuit side of the keyboard centered on the offending key. This is the centre of of the dome. Introduce a tiny amount of the deoxit into the pore on the circuit side of the dome.

Exercise the key and clean up any fluid forced back out the pore during your key press exercise.

Assemble and test. DeOxit works wonders. Still having a problem? Combine the DeOxit exercise with the following. Secure a stiff fine wire and introduce it through the pore. Swizzle it around and remove it. Introduce the DeOxit.

Reassemble and test.

Typically the key responds perfectly after the DeOxit procedure.

Hope this helps.

I would post a picture but I am not at home at the moment.

Geoff.

Go to this link:

http://store.caig.com/s.nl/sc.2/category.292/.f

and scroll down the page until you see the tube. If you do not have or cannot get DeOxit try the pin and some denatured alcohol.


Edited: 15 Apr 2012, 10:09 p.m.


#10

Thanks!

On that page, there is a range of small tubes of that stuff. Which one should I use (what percentage of the solution)?

Or, even better; Which one of these should I buy:

http://www.ebay.com/sch/?_nkw=deoxit%20gold&clk_rvr_id=332812006889


Edited: 16 Apr 2012, 4:12 a.m.


#11

http://www.ebay.com/itm/DeoxIT-G100L-Gold-Squeeze-Tube-100-solution-GOLD-/380429715065?pt=LH_DefaultDomain_0&hash=item589360c679

For some reason my iPad will not function the Link format.

Geoff


#12

Thanks a whole bunch. I ordered it and will commence the surgery upon its receipt.

#13

A picture would also be very welcome :)


#14

The red arrows indicate the pores, the yellow arrows the circumference (edge) of the snap domes.

A.  HALFNUT
B. FULLNUT
C. TITAN
D. STING
E. VOYAGER

Close up of the FULLNUT

Close up of the HALFNUT

cheers, Geoff


Edited: 16 Apr 2012, 2:33 p.m.


#15

You're Da Man.


Possibly Related Threads…
Thread Author Replies Views Last Post
  HP-41(CL): The easiest way to transfer FOCAL programs from a Linux PC to the HP-41 Geir Isene 13 5,845 12-05-2013, 02:40 AM
Last Post: Hans Brueggemann
  Solver issue with HP 17BII - different from 19BII Jeff Kearns 13 4,828 11-28-2013, 02:36 AM
Last Post: Don Shepherd
  Another minor Prime hexagesimal issue Jonathan Cameron 1 1,419 11-08-2013, 02:37 PM
Last Post: Michael de Estrada
  HP Prime Solver Variables Issue Anibal Morones Ruelas 8 3,191 10-19-2013, 09:45 AM
Last Post: Harold A Climer
  Dedicated HP calculator programming-hardware-bug website? Geoff Quickfall 12 2,993 10-12-2013, 11:34 PM
Last Post: Les Koller
  Voyager keyboard issue John Richards 2 1,563 09-27-2013, 07:43 PM
Last Post: John Richards
  WP-34S: Little issue with program step indicator Miguel Toro 6 2,429 09-06-2013, 12:45 PM
Last Post: Miguel Toro
  HP Prime (DVT Prototype) Hardware Details Adrien Bertrand 7 2,942 08-10-2013, 12:04 PM
Last Post: Eric Smith
  HELP! WP-34S (Flashing Issue) Barry Mead 2 1,459 07-15-2013, 04:25 AM
Last Post: Marcus von Cube, Germany
  HP 50g issue Matthew Richards 4 1,910 04-21-2013, 01:27 AM
Last Post: Matthew Richards

Forum Jump: