How do I test the lamp and change the bulb on an Omega C700 enlarger?

It is possible to turn on enlarger with out activating the switch that controls the bulb (lamp). There are usually two power cords, one is for the fans and or height adjustment motor ( if it has one ) and a separate cord for powering and activating the lamp.

You use an enlarger timer connected to the enlarger, The bulb receives its power from the timer/switch.

Once you have powered on the enlarger you then set the timer and pushed the start button? This would activate the bulb for given amount of time you have set on the timer. If you do not have a timer your can find the power cord that activates the lamp and plug it directly into an outlet briefly to test. ( some have proprietary plug ends that only fit the timer)

There are very basic timers and very complex timers. A more complex one is handy and convenient (programmable) but not necessary. You can print with a hand switch and stop watch, wrist watch, wall clock or just count in your head. A timer gives you precision and repeatable control.

As far as changing the bulb, It depends on which head you have on your chassis.

The instructions are in the basic instruction manual that waynef referenced and not to hard to figure out with a little exploration.

The important thing to remember is use a cloth to handle the bulb.