Power supply issues
Most Dell laptop computers have a special external power supply (PSU) which cannot be replaced by a third-party universal supply. The PSU has a chip which produces a special signal identifying the PSU as by Dell and specifying its power, and a special 3-pin connector (minus, plus, and ID). If a power supply not made by Dell is used, and the cable near the connector becomes damaged as is not infrequent after some use, the battery stops charging and the CPU runs slower, although the computer can be used indefinitely so long as it remains plugged in. If this problem is present at startup the message "The AC power adapter type cannot be determined. Your system will operate slower and the battery will not charge" is displayed. This will continue until the external PSU is replaced. A few third-party suppliers make power supplies with specific provision for Dell computers at lower prices than Dell's. It is possible to work round the slowdown, but not the battery charging, by installing a CPU clock utility . On some models (the 9100 for instance), the problem can be worked around by starting the computer without a battery installed and fitting the battery after the computer has booted.
Another problem arises after much use with the motherboard power connector; springy metal parts which contact the outside of the plug lose their springiness and fail to make contact so that power does not reach the computer. The "official" solution is to replace the connector on the motherboard, which requires partial disassembly of the computer and unsoldering of a part with several pins; many companies charge a considerable sum for the work involved. Various simple alternatives have been suggested; for example a thin "skin" of solder on the outside of the barrel of the connector on the PSU (with care not to overheat the connector's plastic parts; and this thickened connector should not be used with other, not faulty, Dells as it will stretch the springs).
These problems are discussed in detail, and solutions and workarounds suggested, in a discussion on the Tom's hardware site .