be repaired by reflowing (resoldering) of the pins on the offending chip, either with an SMD reflow tool, or a soldering iron with a very fine (0.2 mm) tip. Under heavy use, the space bar and enter bar can become detached. This requires keyboard replacement. Under heavy use from opening and closing, the long flex strip connector between the screen and the motherboard can become torn as it tends to rub against internal components in the housing. Typically, the only way to fix this once torn is to replace the flex strip. Fixing unresponsive keyboard keys. Inside the HP 200LX, the keyboard connects to the main board via a "ribbon" that has graphite pads which make physical contact to gold pads plated onto the main board. Unresponsive keys occur when this connection grows weak. This can be fixed by applying conductive silver paint (such as from a circuitwriter pen) to each graphite pad on the "ribbon". One can also use copper tape cut out to small circles. This tape adheres nicely to the graphite pad and actually gives a more definitive long lasting connection than silver paint, although both work fine. This is delicate work, and putting the HP 200LX back together after disassembly may be problematic for those who have little experience with electronics repair. However, the conductive silver paint will fully fix the problem if applied with care. An alternate cause can be corrosion of the motherboard pads to which the graphite pad connects. This can be solved by polishing the pads with fine steel wool. Exceptions to 100% IBM PC compatibility The HP 100LX/HP 200LX's digital-to-analog converter cannot play audio tones; instead, it monitors battery life and charging. The device does not provide the BIOS service (INT 13h) for reading from a hard disk. Drivers have been partially written for this purpose (to boot MINIX 2.0). Other notes The HP 200LX was used on board the NASA Discovery OV103 Mission STS-95 (the last mission of Senator John Glenn) in an Electronic Nose (E-Nose) experiment (the device was developed jointly by Jet Propulsion Laboratory (JPL) and the California Institute of Technology (Caltech)). The experiment, as managed by Dr. Dan Karmon of JPL, was successful. The HP 200LX can play video, and sound files using software from Stefan Peichl in relatively low quality. It is also capable of sound recording, though this is, again, in relatively low quality. There