#2 key problem, china mfr, hp12c, and/or others



#2

#2 key clicks, but does not register unless pushed aggressively. Before trying to maybe fix the problem I thought I would ask here. I have a suspicion that this might not be amenable to repair. The serial number: CN31506945, China.

This belongs to my wife only 2/3 years old. I have an old 10c - more than 20 years old - which has a nice feel to it which the new ones lack.

Stephen


#3

Hi;

is it a regular HP12C or a Platinum? The regular model has keys that are separated pieces, while the Platinum models (including Prestige) have the keys integrated to the upper half case, except for the [f] and [g] prefix keys which are still separated pieces. I have seen many Platinum with loose keys after breaking the two plastic tags in their base, making it hard to get it working normally again.

Cheers.

Luiz (Brazil)

Edited: 22 Nov 2009, 4:22 p.m.


#4

Just checked - Platinum, but I do not know if I understand the difference that you discuss. I have not had the thing apart - yet. I am trying to find out if the click mechanism and switch are integrated into a tiny sealed unit that not possible to repair with my fat fingers.

#5

You should probably ask HP for a replacement.

#6

Since the internal construction of the 12C has changed so many times in the last several years, I don't know what is inside. It might be salvageable but you'll need to open it to find out. Here's how:

Place the unit face down on a soft surface. Remove the battery door and battery. Remove the the two small Phillips screws found there. Carefully lift up/peel off the four rubber feet. Remove the four screws. Lift the back off. Looking carefully at the right side of the unit, look for two small springs standing on end inside black vertical tubes. Remove them and set aside noting that the longer one goes in the tube nearest the display.

Now, have a look at the circuit board. If the unit has a small hole in the board behind each key location, great, you should be able to repair it. If it is a solid board with no openings, it's toast.

If you find the small holes behind each key, you'll need a method to get a few drops of isopropyl alcohol or contact cleaner (no silicone!) inside the hole then press the key a few times to flush out the key contacts. An eyedropper or pipette of some sort will do in a pinch. Repeat at least 2-3 times.

Install the springs and reattach the back with the six screws and reinstall the feet. Should be okay. Repeat the process if needed.


#7

Okay. I will operate tomorrow or the next day. Thanks for the heads-up.


#8

The Platinum is not easily repaired, not what I described above as that only applied to the gold 12C, sorry I did not clarify.

Repair is possible but you have to trim off heat stakes and then glue it back together or possibly suitable screws. Not sure about it though since I've only had one or two of them apart and the results ended up in the circular file.


#9

Quote:
The Platinum is not easily repaired, not what I described above as that only applied to the gold 12C, sorry I did not clarify.

Repair is possible but you have to trim off heat stakes and then glue it back together or possibly suitable screws. Not sure about it though since I've only had one or two of them apart and the results ended up in the circular file.


This AM I operated. I think the #2 key works (better?) now. I am not sure exactly, what, if anything I did, made this happen. The keys are more or less sealed and not repairable by normal humanoids. I did clean out some minor pieces of dust and unrecognizable schmutz.

In case anyone else has occasion to open the Platinum HP12c up I offer these additional comments:

I used a 5/32" drill bit to take off the (thermo)plastic flanges on the stakes - by rotating the bit in my fingers. That was simple and easy. One caution is that one of these (upper left looking at the opened unit) holds the Reset clip to the board. Don't lose the clip. And do not forget to put back during reassembly. I refastened the clip by using ABS primer to dissolve the shavings from the flanges - using that as a glue/welding material. I used (this is slightly obscure) 1/8" foam glazing tape stuck to the back cover to hold the pcb in place when reassembled. I think I voided the warranty. But it has worked for going on 15 minutes now.

Thanks everyone for giving enough information to overcome initial trepidation. A little learning is a dangerous thing. . .

Stephen


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