dirtball = D = disclaimer

dirty power n.

Electrical mains voltage that is unfriendly to the delicate innards of computers. Spikes, drop-outs, average voltage significantly higher or lower than nominal, or just plain noise can all cause problems of varying subtlety and severity (these are collectively known as power hits).

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.