HPLX.NET HOW-TO: An External Speaker Jack


This is a picture of the speaker jack on the side of my 200LX:

The version of this that I have now is fairly primitive, in the early stages of evolution.  There is no volume control, for example, unless you specifically provide one on the headphone set or speaker you plug in.  There are also some slight complications with the wiring inside the unit; I'm working on rerouting the path for a better solution.  However, if you really want to know how you can add an external speaker jack to your 200LX right now, these instructions will suffice.
The jack I chose was from Radio Shack, a 3/32" open-style headphone jack (part #274-292A, comes in a package of two).  The necessary tools are: a soldering iron with a tip small enough to be used as a melting tool (the Radio Shack 25-watt and 30-watt soldering irons work well), and the regular tools needed to open the palmtop (a hex driver or a small regular screwdriver.)  You'll need some very thin insulated wire.  (The thinnest you can find-- 24 gauge is still too thick.  I recommend magnet wire, which is very, very thin.  It's insulated by a coating, not plastic.)  Open up the 200LX and separate the bottom half from the top half.  Once you do that, melt a hole in the area indicated in the photo above.  It should be large enough for the main portion of the jack assembly to stick through it, but not much larger-- you want it to fit snugly in the hole.  (The idea here is to have a tight fit with the hole to prevent sideways movement, and to screw the washer onto the jack to keep it from sliding back in-- thus resulting in a firm and stable headphone jack.)  The diagram below shows where the jack should go:

The box represents the jack.  The two red lines represent the two wires you will use to connect the jack to the springs which contact the motherboard.  The wires follow the path of the metal battery clip.  You may need to remove the plastic walls (directly beneath the box, in the picture) in order to get the unit closed with the jack in.  These will easily remove with a pair of pliers and some bending.  Just don't remove too much, since these walls help when inserting cards into the slot.
This is another schematic of the wiring:

This is what it would look like from below.  You will probably have to remove the plastic walls (again, directly below the box in this diagram) to fit it together when closed.
Note that you can pretty much attach the wires to the springs any which way you please.  I just wrapped them around the springs and left it like that, but it would probably be better to attach it more permanently.
You can then just reassemble the unit and you'll have a headphone jack!
IF YOUR WIRES WERE TOO THICK: your unit will bulge in the middle.  This will create a situation where the middle of the case, not the rubber feet, is the part contacting the surface you set the unit on.  In other words, the 200LX will become high-centered.  This will damage the bottom of the unit, and makes it difficult to type, as it tends to rock the unit while you type.  Solution: use thinner wire.  I'm using 30 gauge magnet wire from Radio Shack.  It comes in a bundle with a couple other spools of wire, cat. no. 278-1345A.  Another good solution: put some bigger rubber feet on the 200LX.  I've done this and enjoy the extra surface-gripping power it affords me.  I even put a strip of velcro on the bottom now, so I can attach it to my fuzzy dashboard in the car, and the big rubber feet keep the strip of velcro from contacting any hard surfaces I put it on, like my desk.

But that's probably information for another page.  :-)


Copyright 1999, David Sargeant.
Last Updated 1-2-1999
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