How do i change the bulb in the nikon eclipse e400 microscope?

Email nikoninstruments(at)nikon(dot)net with some pictures of your microscope and I'll see if we can ID it. Make sure the pics are bright enough and in focus and at a wide enough angle to get a good look at it. Nikon Instruments Microscopes and Imaging Systems

try to find on ebay or on the manufacter support or with technicians who work repairing micorcopes.
this micro. is already considered obsolet \ not in production. i have one. so if it's yours and you know about engineering\electronics it would be better\easier fix it yourself making a new board or adapting other lamp.
i guess that my one the bulb is burn from i remenber and i'm thinking in adapt a led lamp. so add me in facebook that if i change my board i tell u how i do or maybe i could my original board if it's working

Microscope bulbs can be hard to find at a local hardware or electrical store in you area. The best, and cheapest solution is to go to http://www/bulbtronics.com. You will need to know the specification of the bulb in you are to buy online, but if not, their customer service folks are very good at helping you determine what those specifications are, and what bulb you will need to purchase.

I think the number you gave is the microscope serial number, to hope to get help you need to find the model number so people can help. At least post a picture. In general the microscope needs a light source to be bright enough to use. The transformer is meant to provide power to the light. If you use the microscope with a light shining through the object held by a glass slide then the light is below the stage which holds the object. Sometimes on simpler microscopes they have a mirror below the stage and you shine a bright light beam into the mirror and must adjust the angle to reflect the light through the slide. In more complex systems the light is built into the microscope. For opaque objects you must shine the light from above onto the object. If you can't find the official Nikon light source to connect to the transformer, you may be able to get non Nikon light sources. For my stereo microscope for example, I use a LED ring-light I bought on ebay for ~$25. This lights the objects from above and fits around the microscope tube just above the stage.

You can locate an Authorized Nikon Repair Center for India at the following link:

http://www.nikon-asia.com/distributors.php

look for access panels in rear hatch there will be one on each side remove those and there will be 10 ml nuts holding the light housings on remove those then you can access the lights

On ours, we had this same problem and all we ended up having to do was turn the light bulb up towards the black plate and it comes on, then turn the bulb down towards the feet of the microscope and it goes back off.

This might be sign of trouble, because the Nylon gears inside might be worn out. I did not noticed a tension ring on Optiphot 1 or 2. The Nikon S and Metaphot from 1960s to 1976 have Nylon gears with tension ring adjustments.

The Nikon Optiphot 2 tube length is 160 mm DIN finite. It is a 1990 vintage microscope. Any objective lens with the standard RMS thread, -160 engraved on it will work. It will not work with other brnads with the infinity symbol engraved on it or infinity tube length Nikon 200 mm, CFI60 objectives for 2000 vintage to present microscopes. - Lawsen Lew

You should start by changing the bulb, even though it looks ok chances are that it's no longer working. Do the same with the fuse if the new bulb doesn't work.

Test that power is reaching the socket with a voltmeter or a multimeter so ensure the wiring is ok with the new fuse. If no power is reaching the bulb socket, then you will need to check the wiring every step of the way.