Cleaning an Hp41C



#2

Hi there,

I recently buyed a hp41c + Quad mem and X function, but I don't know what hapened but when I received it is has like 1 inch of dust and other thing on it.. I clean it with rubbering alcool + q-tips but under the protective screen there still a lots of dust.. so my question is , how to open it.. also I have one key that don't click
anymore and is a little bit harder to get entered correcly, so, do
opening the calc will enable me to help this problem too,

So do somone have picture of how to open a FullNut starting with 20 and tips on how to clean the calc...

Thank you all,
Xavier LaRue


#3

Xavier,

I have had the same problems in the last couple of months with machines I bought from 'crooks' on eBay (sorry friends - it's the most polite word I can use). In fact I recently bought a 'MINT' HP-41CX only to find it had tons of scratches on the sides, matte (non-shiny) keys probably from overcleaning, and the 'clean without corrosion' battery contacts to be FULL of corrosion!!!

In any event, I have read posts from before where people used 409 cleaner on the keyboard. You can open the machine by taking the four pads on the bottom off and unscrewing the four screws. There are some posts lately to me, suggesting to be very careful with HP-41C and HP-41CV machines, where HP-41CX machines are easier. The colleagues were suggesting to be careful with the former ones as the boards internally need some pressure to stay together. In fact, later machines that were Halfnuts (even HP-41CVs) would not be difficult to open. (Halfnuts are the ones with the rounded edges on the display - you probably don't have one of those).

Once you open the machine you can use distilled water and a Q-tip to clean the circuit boards inside. I would use some 'Dust Off' myself as well. That is the can that has some kind of condensed chemicals (difluoroethane). As far as cleaning the battery contacts, there was some discussion recently that one could use lemon juice or vinegar, and coat them with butter from what I understand. I just used lemon juice and a Q-tip and it cleaned most of the base deposits on the battery contacts of my machines (about 90%). I think the relevant post was called: 'Battery leakage and cleaning' but for some reason I cannot seem to access it, maybe due to the passworded changes to the site that were implemented lately by Dave Hicks; he can comment if that's the case.

I hope that helps a little bit.
Good luck,
Andreas


#4

I think it was me who said something about butter. DO NOT DO THIS! You can do this on a car's battery, but I would not do it on a 41C.

Also do not scrape the battery contacts, they are just thin foil!

Btw, repairing broken keys is not as easy as on the classic model

Edited: 17 Mar 2006, 3:53 a.m.


#5

So the point it,

Until it's completly broken.. don't fix it ?

Xavier LaRue


#6

Key malfunction due to dirt => fixable

malfunction due to broken domes (the key is lower than other keys) => bad luck

The reason: You do not have access to the keyboard contacts. The whole keyboard assembly is fixed with heat-stakes to the front plate of the case. Maybe professionals can fix broken keys (fixthatcalc.com).

#7

Hi,

I also have had some problems with the 41C Series ... my advice is, try to get some pictures of the calcs you are buying on eBay, you can immediately tell the condition of a unit pretty surely by how it looks on a good picture ... and don't forget to ask a picture of the battery contacts.

Anyway, also on the spirit of this topic, does anyone have a good method to access the keyboard on the 41C series? Like a member said the circuits are pinned to the front plate by heat stakes, so does anyone found a good method of removing then and the put all back?

Regards,
jbssm


Possibly Related Threads...
Thread Author Replies Views Last Post
  Cleaning old slide rules aurelio 3 646 09-18-2013, 03:25 PM
Last Post: aurelio
  Cleaning exiting library programs patryk 2 425 09-14-2013, 12:36 PM
Last Post: patryk
  How to check / repair a HP 82106A module for HP41C calculator ? Eduardo Mingo 13 1,160 01-07-2013, 11:05 AM
Last Post: Diego Diaz
  A simple question about the HP41C or HP41CV Antoine M. Couëtte 6 718 12-16-2012, 04:06 AM
Last Post: Antoine M. Couëtte
  HP41C repair ? Michael Paul 4 545 09-30-2012, 11:26 AM
Last Post: db (martinez, ca.)
  A cheap HP41C for sale...........999 EURO only aurelio 4 614 06-04-2012, 03:46 PM
Last Post: jerome ibanes
  HP41C: Factorial (kind of) in MCODE Frido Bohn 7 805 05-26-2012, 09:18 AM
Last Post: Frido Bohn
  Woodstock/Spice Keyboard Cleaning Revisited Matt Agajanian 0 347 05-12-2012, 03:43 PM
Last Post: Matt Agajanian
  Picture of HP41C from "The Dream is Alive" Christopher Johnson 0 271 04-20-2012, 02:38 PM
Last Post: Christopher Johnson
  HP41 Cleaning Advice John Abbott (S. Africa) 5 604 04-10-2012, 01:51 AM
Last Post: John Abbott (S. Africa)

Forum Jump: