Archived 2013-12-08
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How to disassemble the HP 100LX, 200LX and 1000CX Palmtop

Introduction:

This page gives you an idea about the steps necessary to get to certain inner parts of the HP 200LX palmtop. Since the hardware is almost identical, this article also applies to the Palmtop models HP 100LX and HP 1000CX.
The steps have to be executed in the order shown here; you cannot take apart the screen without first having to take apart the whole 200LX body, for example.
Do everything very carefully, and be aware that you risk the life of your palmtop, if you take it apart. I will not be responsible if any of the steps described here will damage something, for me this procedure works, and if it doesn´t for you, it is not my fault! Do not do anything described here if you do not feel comfortable with it! It is tricky, and if something goes wrong, you can easily make the palmtop totally unusable.

All data will be lost after the process! So back up everything before you open the palmtop.

The following picture shows how the HP Palmtops are assembled. The picture actually shows a 95LX, but the other models (except the OmniGos) are very similar.

Main part:

Begin with a clean table surface.

You need the palmtop, a credit card, a Torx-6 screw driver and some small ordinary blade screw drivers (not shown on this picture).

First, remove all removable parts (IR / backup battery cover, backup battery with its holder, then the battery door, the main batteries and of course the PCMCIA card, if there is one in the slot).

Remove the four bubber feet using a small blade screw driver or your finger nails.

Remove the four screws under the rubber feet with the Torx-6 screw driver.

If you later want to remove the screen: Remove the two hinge caps now. Open the palmtop so that screen and keyboard have an angle of 90 degrees, then use your thumb nails to apply force behind the hinge caps. It may be necessary to wiggle them a bit:

Close the palmtop again, now we will open the body. You will need the credit card soon. Make sure it is accessable with your right hand. Begin to pry apart the body carefully in the corner where the PCMCIA eject slider is.

Put the palmtop onto the table so that the backup battery side shows down and the PCMCIA slot shows up.
Now take the credit card, stick it a few millimeters into the gap (only a few millimeters!! Not more than necessary, because you would damage the keyboard cable with the following...!) and slide it slowly down through the gap in the direction of the right palmtop side. Stop when it is in the posistion shown in the picture below and lever the two body halves apart at this point. Here is the position where the two halves are kept together with the strongest force, because here is the screen-mainboard connector, which is a pressure contact.

Now the front side of the palmtop body should be open a few millimeters. That was the most difficult part.
But in the range of the battery compartment the body halves still hold stronly together!

Pry them carefully but also forcefully apart exactly where the plus pole of the batteries show to. But seperate them first only for some millimeters, because...

...it may be that the battery contacts still stick in the motherboard battery connectors. You can see this through the gap. If this is the case, use a small screw driver to flip them out. See the right picture: The right one of the mainboard connectors (left and right side of the big yellow capacitor) still holds a battery contact which has to be removed.

Now you can safely separate the two halves.

If the battery contacts had to be manually removed from the motherboard, they are probably not in their right place in the bottom shell anymore. Press them back into their place: The left image shows that the right battery contact is not in place.

Now we can almost remove the motherboard. Only the screen cable has to be detached from the motherboard first. Use a small screw driver to open the connector (left image shows closed, right one the opened connector). When the connector is open, you can easily remove the screen cable.

Now take the mainboard out of the body. It is only lying there, no further screws.

Still not enough? You want to remove or even take apart the screen? ;-) Okay. Here we go:

First, we must separate the screen case from the body. For that purpose, we first have to take out the white screw-like disks in the battery compartment. "Screw" them out by spinning them with a screw driver, no matter in which direction, by exactly 45 degrees. Then you can remove them.
Note that there are one or two grooves on one of the four sides of each white disk. When you reassemble the palmtop, these grooves should point into the same direction as they did before you removed the disks, i.e. towards each other. This is for the screen cable to have the needed space.

Flap up the screen to 90 degrees, then press the hinge tube (the long black tube between the hinges) gently together and pull it away from the body. Again, only a few millimeters first, otherwise you could damage the screen cables. Begin on one side and proceed in the middle, later pressing and pulling on the other side. On the right side the hinge is mounted on the case body with a meetal pin in a hole of the case. This could need some more force to be pulled out, sometimes it's easy. Don't apply brute force. If necessary, push from the other side of the hole with a small tool.

When the tube is separated from the body, gently slide out the orange screen cable through the hole and even more carefully slide the silver ground contact into a position so that you can stick it through its hole out and remove the screen entirely from the body.

Now remove the screen cover from the screen. Lift in in one corner carefully with a small screw driver and begin to pull it off from that corner. Be careful, since you need a lot of force to pull it off.

You will now see four more Torx-6 screws. Remove them. It´s easy.

To separate the two halves of the screen case you need the credit card again. Begin in the upper left corner, take most care in the range of the latch, since the case plastic is very thin there, then pry the halves apart on the bottom side, but stop before you get to the right hinge! Don´t ever take apart the right hinge and take care you do not break anything in the surrounding of the right hinge!! Also take care with the little latch which holds the palmtop closed when it is not in use. It has extremely thin plastic springs which can easily break (the picture below shows a broken latch)..

Try if you can lift up the screen easily on its left side from the flat cable connector. If not, you have to lift it gently using a screw driver. But take care not to damage anything on the circuit board. Now you can bend the two case halves apart and take out the screen. On the right side you will have to lift the screen up from the right hinge, don´t force it into the left direction, but lift it up!

Now you have removed the screen. Do you really want to do more? Take apart the keyboard?? Well, if you are sure...

The keys are held together by a plastic grid, and this grid is mounted on the LX body by many, many little plasic pins. You see these plastic pins from under the keyboard as little black (number pad) and grey (other keys) dots. You will have to push every single pin with a small centre punch or similar out of the hole. Once you have done this, you can lift up the plastic grid with the keys.
You can remove the keyboard cover (where the additional meanings for the keys are printed onto) only in a convenient way before you pushed out the pins. So do it before or never. As with the screen cover, use a small screw driver and begin in one corner. Then pull it off entirely.

Once you have removed the cover and the key grid you will see the different foils involved into the keybaord functionality. I have also removed the contact foil for you (the white thing), which should not be necessary in general, and the following picture shows all keyboard components in the order of appearence from the top down (on the picture from left to right):
Keyboard cover, key grid, bubble foil, distance keeper foil, contact foil with motherboard connector.

Here are detail pictures of the keyboard components:

And here you see an overview picture of the entire disassembled HP 200LX:

Well, that´s it. Now reassemble everything. You can do it in the exact reverse way you disassembled the LX.
If you are interested in disassembling the screen module for repair or for backlight upgrade, please have a look at my backlight page, especially the instruction sheet describing the upgrade process.

Good luck!