HPLX

You can find the serial number engraved into the bottom of the Palmtop. There are rare cases where there is no serial number, or where the serial number is printed on a paper label which is attached to the bottom.

100LX, 200LX, 1000CX, OG700LX

Pattern:
XXYWWNNNNN

XX = country of manufacturing (SG = Singapore ...)
Y = year of manufacturing, last digit (6 = 1996)
WW = week of the year of manufacturing
NNNNN = Number of manufactured units before yours during the specified week

Example:
The serial number SG40201880 means:

• SG: Made in Singapore
• 4: Manufactured in 1994
• 02: Manufactured in the 2nd calendar week of 1994
• 01880: 1881st unit made in that week.

95LX

Pattern:
ABx AAWWCNNNNN

AB = no special meaning
x = language (F: French, D: German....)
AA = Year-60 (32 = 1992)
WW = Week number
C = Country of manufacturing (S = Singapore, A = USA)
NNNNN = Number of manufactured units before yours during the specified week

This article is related to the Palmtops HP 100LX, 200LX and 1000CX, partially to the OmniGo 700LX. The 95LX cannot be upgraded in the way described here.

See also: Tutorial: Disassembly of a 200LX

If you are interested to have your Palmtop upgraded by an expert, please have a look at my HP Palmtop related products page.

The double speed upgrade is a way to make the HP Palmtop faster. It will double the CPU frequency and thus approximately double CPU-intensive tasks. Also access to other hardware components in the Palmtop is done with higher speed, as the hardware components allow this. So, the screen updates are quicker with a doublespeed upgrade, for example.

The upgrade is done by replacing the original quartz crystal which clocks the CPU by one which is twice as fast. The original crystal is abt. 15.8 MHz, which lets the CPU work at a speed of about 8 MHz. The upgrade crystal should have exactly 31.673 MHz, which speeds the palmtop up to about 16 MHz. Such a crystal can be bought from Times2Tech. A 32 MHz (or even faster) crystal could also be used, but this may lead to some problems with time-critical hardware components, such as the PCMCIA port and the communication ports (serial and IR).

Position of the quartz crystal on the motherboard:

An original single speed quartz there is labeled 158 CP52.
The double speed quartz by Times2Tech is labeled F31.673.

If the quartz is placed accordingly, you may see if you have a single or double speed quartz installed by looking through the backup battery slot:

You can easily check, if you have a speed upgrade installed, if you are unsure:
First, close all applications and save all open files. You need to reboot in the next step.
Switch the palmtop off.
Press ESC-ON. This shuts down the running system session and brings you into a self-test routine.
If you can not read the screen, it is double speed for sure.
Else: Select "Timers" and hit Enter. The timer test runs.
If the timer is in the 20800 range or so, the LX is double speed, if in the 10700-10914 then single (original) speed.
Afterwards, reboot the palmtop by pressing Ctrl-Alt-Del.

To make everything work with the upgrade, a driver is needed. For the Times2Tech upgrade, it is the spd31.sys or spd31.exe driver, which comes with the upgrade (or download it here).
If you use a 32.0 MHz or a 31.0 MHz crystal, you need the clkup32 or clkup31 driver. For crystals with speeds faster than that there is no special driver (and due to the risks of making the palmtop inoperational, it is not recommended to use such crystals).
There is another driver called clockup (download clockup.lzh here), which comes with source code and has a system clock correction feature. Maybe it can be used with exotical crystals. If you buy a crystal not sold by Times2Tech, make sure it is no overtone (harmonic) quarz, but the nominal speed is the main frequency. Otherwise you would need to filter out the (slower) main frequency.

Please note:
If another quartz than the exact doublespeed 31.673 MHz quartz (made by Times2Tech) is used, this may cause slight problems due to non-exact timings. For example it may be that the serial port / IR port does not work correctly anymore at higher baud rates. This usually does not happen, if you use the correct driver, but I have heard of cases where there are problems. It seems to depend on the specific hardware due to component value tolerances. If the quartz has been installed professionally, it usually is no problem to replace it by the original 15.8 MHz quartz again in case there are problems with the doublespeed upgrade.

This article is related to the Palmtops HP 100LX, 200LX and 1000CX. The OmniGo 700LX and the 95LX cannot be upgraded that way.

See also: Tutorial: Disassembly of a 200LX

If you are interested in a RAM upgrade for your HP Palmtop, have a look at my HP Palmtop products page or contact me.

There are pages excellently describing do-it-yourself memory upgrades for the 200LX some of them without the need of a daughterboard:

• The Japanese site http://home.r03.itscom.net/forestar/PJ128M.htm shows several different upgrades, from 16MB up to 128MB (!!) internal RAM. 
• The article Another memory upgrade by Carlos Izzo Videla describes a piggyback upgrade from 2MB to 4MB or 6MB of a 200LX with 2MB on-board memory (without using a daughter board)
• The page http://www.upl.cs.wisc.edu/~orn/tech/200lx.html by Rudy Moore describes how to add 2MB to a 1MB or 2MB 200LX, ending up in 3MB or 4MB total memory.

For all upgrades involving a daughterboard, i.e. a RAM expansion module, you need a daughterboard socket (connector) on the motherboard. Some motherboards don´t have this socket, some do. 4MB 200LXs and 2MB 100LXs always have one. All 200LXs which don't have one installed have at least the soldering pads for such a connector. Here is the datasheet of the needed connector. You can buy such a connector from Thaddeus or Rundel. These models can be upgraded with a daughterboard: 100LX 2MB model, 200LX all models, 1000CX all models.

This is a 4MB upgrade daughterboard by Times2Tech which upgrades a palmtop with 1 MB on-board memory to 5 MB, a 2MB motherboard to 6 MB. This board is simply plugged into the RAM socket, no additional wires are needed:

This is an 8MB upgrade daughterboard by Times2Tech which upgrades every kind of basic configuration to 8 MB, because the on-board RAM is removed entirely:

This is a 32MB upgrade daughterboard by Times2Tech:

The following pictures show the additional wires which are necessary for the 32MB memory upgrade. Some pins of the CPU chip have to be removed from the mainboard and wires have to be attached to them. These are pins 24 and 25 from the right on the pin row which faces the battery compartment. The wires lead directly onto the memory upgrade board. Pin 24 (the right one) leads to the pad labeled "A1" of the Times2Tech 32MB upgrade board and pin 25 (the left one) needs to be connected to pad labeled "A10".
This is a very tricky job and not recommended to be done by people who are not experts!

The pictures below show the 64MB upgrade board. 3 additional address lines must be connected to the CPU for that kind of upgrade. The daughter board is much larger than the boards of the 32MB and smaller upgrades. There are also 64MB upgrades which have the same small daughterboard size as the other upgrades. Klick on an image to view a larger one with more details.