Microscope field does not change as mechanical stage is moved

Maybe there is some wear at the thread where the stage fits, causing that the stage cannot hold.

Hi Faye , we will probably need more info

Does the stage move freely on its own without the course focus knobs

Can you move the stage up and down with either of the course focus knobs

Instrument details / picture would help .

The gear that runs along the stage is probably loose. It is held in place by three screws. If the gear is nots parrallel with the X/Y axis gear it will bind. My guess would be that it is the two outer ones that are loose, thereby creating a see-saw affect.

Send the microscope to a Delta Optical Instruments, Inc. for an estimate and repair. Email: [email protected]

Starting at the bottom of the Compound Microscope scope working up: The base of the scope houses the illumination system and the field lens. It also provides weighted stablility.
The field lens is where the light comes out of the base. This lens focuses the light from the bulb directly into the substage condenser.
The arm of the scope supports the rest of the scope.
Directly above the field condenser is the substage condenser. The substage condenser collects the light and condenses it further into a more concentrated beam of light. With the substage condenser you can control the amount of light and to some degree the defraction of light. This is helpful in adjusting the "contrast" in the image.
Working up, you find the "stage" which is a platform to support the specimen. The stage may or may not have a specimen holder and a set of specimen holder control knobs.
The magnifying lenses are called the objectives. They look like barrels pointing down at the stage. These are usually marked 4x, 10x, 40x, and 100x. These magnifications are further multiplied by the power of the eyepieces which are usually 10x. So, when using the 4x you are actually seeing the specimen at 40x and when you are using the 10x objective you are actually seeing the specimen at 100x and so on. The 4x is used to "scan" the specimen so that you can find the most interesting area and then focus in further on that region. It is very hard to find exactly what you want to focus in on starting with the higher magnifications. Always start with the low magnifications, 4x or 10x.
The objective lenses are mounted on a rotating turret for easy selection.
Moving on up the scope is the head. It is comprised of the eye tube and the eyepiece. If you have two eyepieces your scope is referred to as a "Binocular Compound Microscope". If you have only one eyepiece, your scope is a "Monocular Compound Microscope".

With one hand push the stage down, and with the other turn the coarse adjustment down. It's a cog alignment issue. The coarse adjustment cog should be turning in order to catch the stage track.

You need to tighten the coarse adjustment so it generates enough friction to keep the stage in place. How to tighten it will vary from scope to scope, but most just have the screws on the knob (metal circle inside the knob with two holes in it). To adjust this type, you'll need a special key wrench.

Are you able to focus on the specimen? Is the problem the same if you switch to a higher magnification lens?
Could be several things, a slider half way in, a turret not clicked in to the notch, ie condenser, a filter partway in.

I think your problem lies in the way the stage is limited upwards. On top of the stage, right behind it where it slides against the arm, there should be a little screw.  This screw limits the movement of the stage to a certain point upwards.  If the limit exceeds the adjustment gear and its opposing track, then the stage just goes up one notch and then it clunks down.  If you screw it down the stage is limited further down, if you screw it up it's limited a bit higher.  The point of this screw is to prevent objective and slide damage.  Try adjusting this little screw a bit further down and see if it still 'clunks' when you turn it up.  After that we may work on properly adjusting it.  If not, please post again with whatever detail you can provide to aid you with this problem further.

Not really a solution, but anything is better than a posting that get's NO response. It sounds like the rack and pinion drive has collapsed. If you're good with your hands and have a knack for things mechanical maybe you can dissassemble the stage mounting and see how it's meant to work. If something has come loose rather than broken maybe you can fix it. If teeth have stripped from the drive gear - you may be unable to effect a repair. I guess trying to fix it is better than doing nothing. Have a good 2008

kevin