If you want more memory, the wisest course is to contact the people at Times2Tech. While I haven't used them, I've heard very good things about them and their product is definitely cost effective. Mack at Times2Tech was helpful answering a couple questions I had about the 200LX - Thanks!
Ask yourself these questions if you're still interested in doing this modification: Do I solder well? Do I have the right equipment to solder on small parts? Will it be okay if I accidentally destroy my PDA?
In a nutshell, the 200LX board has been designed to take a daughter card that contains memory. I've soldered a memory chip directly to the pads on the connector that would normally hold the daughter card. The DRAM chip that I used was a Samsung KM416V1200BJ-6.
The speed of this part is a little quicker then I really needed, but it is the architecture that's important. The 416V1200 is a 1M x 16 DRAM with 1K refresh blocks. Amusingly, a 4K refresh block size would have dropped current consumption by half, but the 200LX isn't set up to handle that part.
Next, I soldered leads to all the pins on my DRAM, except for the No Connects (N.C.). Here's a table of the pin numbers and signal names on the DRAM:
Once the long-legged, DRAM beast was created, I was ready to solder it to the motherboard. I Ohmed out the connector with 200LX's DRAM already on the board and came up with the following conversion chart:
Once the part was wired up, I rigged up my power supply and reconnected enough of the innards to test it out. It worked on the first try, so I was pretty pleased.
The other disappointing side of things is that the current design is ancient electronically speaking. The 200LX should be redesigned for power savings and speed.
It's most likely a key failure. Sometimes the keys get a little soggy and don't contact with a regular press-- sometimes you really have to push them down hard to get it to work. Try doing a keyboard test, or try using the Fn key and see how hard you have to press to get it to show up. The good news is, if it IS a key failure, they're usually completely fixable by cleaning out under the contact pad.
A bit more involved:
I recently had the SAME problem: resolved that easily by using a so-called 'contact-spray'.
Switch off the machine, use the spray gently around the key. Press the key a couple of times (30-40) and then power on the machine and see whether problem is solved. In my case I had to repeat the above descriped step a second time. Afterall problem resolved within 2 minutes.
More involved yet: (but it solved the problem for me!)
I had similar problems. It turned out to be a bad keyboard connection. If the problem occurs again, just put some pressure on your case in the lower right corner, where 0.=+ is located. If this solves your problem, you first should check, if the screws of your case are loose. Fix them and the problem should go away. If the screws are fix, you might have to open your palmtop and clean the keyboard connector cable. However this is not simple and you should do it only, if you know how to open the palmtop. The speed upgrade comes with a detailed explanation.
(Note: I used 2-propanol to clean the gold contacts on the keyboard connector then reassembled. It even worked with the memory upgrade that I performed a year ago!)
I found out, that the 32MB upgrade, which sits just under the number block, adds a little 'belly' to the keyboard and could be the reason for a bad keyboard connection, which works on pressure between the case and the motherboard.Rudy Moore This guide © 1997, all rights are reserved.