|Re: how do i open hp 21?|
Message #5 Posted by Vieira, Luiz C. (Brazil) on 30 May 2005, 4:14 p.m.,
in response to message #1 by matthijs de boer
Arnaud's suggestion is a very good one, leave it without the batteries for a while till it dries out. You can also clean the contacts to avoid residual after the water evaporates by using destilled water, so you might need to open it, too. The image below is the inside view of a very similar case, the HP25 case:
This is the front view. As you can see the LED display on the top of the image, there are two holes right below it, close to the battery compartment. These are the holes with screws, and if you look at the back of the calcualtors, the two top rubber feet hide them. You should remove the rubber feet and unscrew them. These are the only screws keeping the half cases together.
So, remove the batteris, remove the rubber feet, remove the screws and gently separate the two halves, keyboard and back case, top part first. They separate slightly, then you gently slide the keyboard till it can be detached form the back case. After that, you'll see that the keyboard is connected to the mainboard through many connectors, as well as the display. You can separate each one and clean the mainboard plus the keyboard separately. DON'T TRY TO CLEAN THE LED BAR! It is easily dammaged and there is no replacement.
If you believe you cannot suuceed, ask for help. The HP21 is a rare calculator and it would be sad loosing it...