A technician is a person who can upgrade and repair weapons and armor for a price. Technicians were introduced in S.T.A.L.K.E.R.: Clear Sky and continued on to Call of Pripyat.
Job description
A technician's price on repairs will depend on the damage done to the item and the item's quality. Generally, the more beaten up and the more expensive the item is the more money is needed to repair it, for example: A heavily damaged Leather Jacket will cost only a few rubles to fully fix it but a heavily damaged "Bulat" armored suit will cost more than 10,000 rubles just to fully fix it.
A technician can also upgrade weaponry and armor and the upgrade's price will ultimately depend on the weapon's caliber and the armor's type but most weapons and armor will use the same upgrades for their caliber type and armor type with only a few custom upgrades for each item for it's unique characteristics.
It should be noted that there is NO technician that knows how to upgrade all the equipment in the game, and the player will have to go to different technicians from different factions if the equipment he had cannot be modified by a certain technician, though all technicians can repair all the equipment in the game regardless of type.
Appearances
Clear Sky
Except for the renegades every faction has a technician.