I changed the lamp of my toshiba tdp-s20 but how do i reset the time

SOURCE: Toshiba TDP-S20 lamp problem

The lamp ballast which ignites the lamp has failed it sounds like. The red flashing lamp is the tell tale sign with a good lamp installed. Make sure the lamp door is closed too, there is a door switch that can also trigger the red lamp and no startup. There is a company in San Diego CA that can repair the unit called PROJECTOR DOCTOR

SOURCE: Toshiba Lamp Reset - How?

Not positive, but I would assume the same as my Toshiba.
With the on, input, and menu buttons held down, insert the power cable.
Hope this helps, NGK

SOURCE: HOW TO RESET TOSHIBA TDP-S8 LAMP

after installing the new lamp, hold the volume top & bottom key simulteniously, when green light indicate at panel start the projector & go to service there you may found reset lamp ? press yes the lamp will reset.