Dell 1850 User Manual page 23

Replace with the new lamp.
6
Tighten the screw that secures the lamp.
7
Replace the top cover and tighten the screw.
8
Reset the lamp usage time by selecting "Yes" for Lamp Reset in the OSD
9
Power Settings of the Advanced Settings menu. When a new lamp
module has been changed, the projector will automatically detect and
reset the lamp hours.
CAUTION:
LAMP(S) INSIDE THIS PRODUCT CONTAIN MERCURY AND MUST
BE RECYCLED OR DISPOSED OF ACCORDING TO LOCAL, STATE,
OR FEDERAL LAWS. FOR MORE INFORMATION, GO TO
WWW.DELL.COM/HG OR CONTACT THE ELECTRONIC INDUSTRIES
ALLIANCE AT WWW.EIAE.ORG. FOR LAMP-SPECIFIC DISPOSAL
INFORMATION, CHECK WWW.LAMPRECYCLE.ORG.
Lamp Disposal (for the US only)
Maintenance 23