The Museum of HP Calculators

HP Forum Archive 14

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Disassembling dusty HP27S
Message #1 Posted by Erwin on 14 Jan 2005, 6:23 p.m.

I bought a very dusty HP27S, where dust came inside and reduces the visibility of the display. In my opinion the one possibility to clean is to open the calculator, but I couldn’t find any way without applying brut force. So I gave up.

Is there an easy procedure for opening available.

Erwin

      
Re: Disassembling dusty HP27S
Message #2 Posted by Randy on 14 Jan 2005, 6:33 p.m.,
in response to message #1 by Erwin

Opening it will not get you any closer to the display, it's behind the logic board. The best way to clean is a couple of cycles through an ultrasonic cleaner. If that is not available, form a point on the end of the tube on an air blaster can. Stick the point in the case seam and blast away. Work from both sides and you should be able to get most of it out. It can be VERY stubborn.

Don't use any mechanical methods, you'll only scratch the inside of the lcd or polarizer, they are very soft materials.

            
Re: Disassembling dusty HP27S
Message #3 Posted by Matthias on 14 Jan 2005, 7:52 p.m.,
in response to message #2 by Randy

Well, I´m a layman in ultrasonic cleaning. As I know, you put the dirty unit in the cleaner and fill it with undistilled water. But what happenes with the electonic parts in the calculator? Does the water damage the electronical parts? What is "allowed", what is "not allowed", because you damage parts?

Matthias

                  
Re: Disassembling dusty HP27S
Message #4 Posted by Randy on 15 Jan 2005, 12:10 a.m.,
in response to message #3 by Matthias

The water will not damage anything.

So long as you always remove batteries and when cleaning is done you shake out all excess water and dry in a warm place all you will get is a clean calculator.

      
Re: Disassembling dusty HP27S
Message #5 Posted by Erwin on 16 Jan 2005, 6:56 a.m.,
in response to message #1 by Erwin

Thank for helping


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