EXFO Xcite 120Q light source
This light source provides relatively broad spectrum illumination for fluorescent imaging and other types of imaging. Its light is routed to microscopes and other devices via a liquid light guide.
The spectrum it produces is shown below:
The lamp must remain on for 30 minutes after it is turned on and remain off for 15 minutes after it is turned off to avoid rapid temperature changes that shorten the life of the bulb. It has a blue dial that allows you to filter the light that is transmitted (0%, 33%, 66%, 100%).
The bulbs (called "lamps") normally last a really long time (1500 hours is expected, we've had almost 3000 in the Fitzpatrick lab). But we did once have a dud lamp. I don't know how uncommon this is but one should err on the side of having more lamps. Replacements can be found at the Xcite store website.
Also, we once had a bad liquid light guide, which can appear a lot like a bad lamp (dims or blocks light totally). They fail every 3 years or so, or more often if they get bent or something. They are probaby more fragile than glass fibers. Replacements can be found at the Xcite store website.