LOOSE FOCUS SHAFT

Unfortunately, it does not look like there is a replacement part available for your Farberware Toaster Oven model #510615. You may want to consider purchasing a new toaster oven.

The Celestron manual for this scope has nothing to say, but on the underside of the focuser assembly, between the 2 focus knobs, you may see 2 screws.
They might be thumbscrews or some other screwhead type. One is the adjustment for the focuser internal clearance, or looseness, and the other is a focus travel lock.
If present, try backing both off 1/2 turn from tightness, and then experiment to see which is which. The focus lock will have no effect until tight, when the focuser will cease moving, as is now. The other screw will gradually remove looseness and rattle from the focuser until it just moves smoothly, with no back and forth loose feeling at the knob.
If neither of these screws is visible you will have to take it to a binocular and telescope shop, where they should not charge much.

The KODAK Carousel 750H was manufactured from roughly 1971 to 1981.
If you can push the focus knob toward the outside of the projector and manually remove the lens, then the problem is the gear on the focus shaft (the shaft the focus knob turns). The gear has either cracked and fallen off or is cracked and slipping on the shaft. Either way, the focus shaft needs to be replaced by a factory-trained repair technician.

First, a scope of this grade will not be completely in focus as you move from one magnification to the next. But it should be close enough that you do not loose your point of interest.
Be sure you are not pressing down on the stage specimen platform as you change magnifications. It is very sensitive to pressure. Also, be sure that the coarse focus tension is tight enough that the platform is not drifting down imperceptibly as switch magnifications. Look through the scope and watch if the image goes out of focus while you are watching it. If so, you have what is called "stage drift". This is corrected by tightening the tension on the coarse focus knob.
The tension adjustment is on the coase focus shaft. It looks like a chrome ring with about 3 holes in it. There should have been a strange looking tool that came with your scope. It is used to adjust the tension. If your specimen is "drifting" out of focus, simply tighten the tension ring a little bit at a time until the specimen no longer goes out of focus. Do not get it so tight that it is not easy to operate the coarse focus knob.

pull of the knob
put a smill flashlight down the selector shaft
you should see a small adjustment screw
probably a tiny flat head
very small turns
start from the lowest setting if you start from the highest you could loose your low flame below the grid
always adjust fromt the lower settings

some of these units are factory set and cannot be adjusted by the consumer,,,,unless you want to install new adjustable gas valvews

Squeeze the spool cover as you turn.

The right hand shaft knob contains the coarse focus locking clutch adjustment mechanisim( big name-simple design). This solution applies if you have the model with the fine adjustment wheel mounted in the base and may or may not apply if your fine focus is in the left-hand knob.

Inside the right hand knob ( as viewed from the rear of the scope) is a threaded disk/nut which has two pins (Slightly and for reasons I don't understand: they are offset vertically, they have different pin diameters and different pin lengths) In theory, they lock into the bushing within the knob proper to keep tension on the clutches while keeping the knob from falling off.

The repair can proceed in two ways depending on if the disk/nut has totally been unscrewed from the focus shaft.

Gently pull the left knob and as you do turn it slowly to see if the pins reseat. If they do you'll feel a slight lurch outward of the knob. Hold gentle outward tension( so as the pins remain seated) as you turn the knob clockwise until the slippage in the clutches is so lessened that your knob is firm and the focus adjustment is operating to your liking.

IF that didn't work it is likely that the threaded disk/nut has come off the shaft and will need to be reset and screwed back down. The disk is easily cross threaded and you'll need tweasers or micro plyers or a hemostat and/or a flat headed finishing nail. Plus I recommend a small bottle of LOC-TITE(tm) semi-solid thread sealer--NOT the kind that freezes the threads

As you unscrew the knob counter clockwise pull on the knob to slid it off the shaft it should come off in your hand revealing about 6-8 washers on the shaft. These are the clutches so be careful not to loose them.

The knob should have a slight rattle and that is the disk nut. To get to the disk/nut put a small finishing nail head first into the shaft whole and push to release the plastic knob insert cover out being careful to not loose the disk/nut.

To clean the threads and insure an easier repair screw the disk onto the focus shaft to insure the threads are clean.

This next part works better with the scope lying on its left side.

This part is optional but not necessary to get the scope back in operation. Place a tiny amount of LOC-TITE thread sealer on the shaft threads. This will make the knob clutch adjustment more stiff but will also reduce the likelihood that the knob will be adjusted out too far again. The loosening occurs when the knob is turned before the operator realizes the pinion gear limit has been reached or by someone who dosen't understand correct opperation of the focusing assembly.. So long as the clutches are engaged the and there is no slack in tension the disk/nut shouldn't come off the shaft again.

Observe the pins in the disk/nut and match them up with the holes in the aluminium/brass knob bushing. You'll have to wiggle the disk around to get it reseated properly. Once you do, hold the disk firmly against the bushing to keep the pins seated as you put the knob back over the shaft, pushing it all the way down against the shaft.(The clutches are springy so don't worry about it locking in place just now).

You may prefer to hold the disk/nut and knob firmly with a finger and spin the left hand knob counter-closkwise for easier threading of the nut but remember this will also move the focus arm. Not a problem if you start with the focus in the range centered.

If using the right knob: Turn the knob clockwise feeling for the threaded shaft maiting back up with the threads. IF it cross-threads, back it off try again. Once the threads are engaged keep the outward tension on the knob so the pins don't slip out. When you/ve screwed it down far enough, the clutches will take up the slack and keep the knob from slipping away from the disk/nut. You'll know the clutches are engaged when the focus shaft turns.

If you are happy with the repair slip the knob cover back on and snap in place. It if falls out place a little of the thread sealer on the rim and try again.

If you like this solution it took me an hour to write it up. Please consider volunteering an hour with a local non profit. I support the American Red Cross, Habitat for Humanity and the USO.
Regards

Hi,
Open the end where the light is, look for a set screw at the point where the tension assemly enters machine. try tightening that. If that doesnt work, post a reply comment and I will tell you where to go next.

You will need to remove the clutch release knob and the 3 eared positioner (the clutch) under that knob. Reposition the clutch on the shaft, put the knob back on and see if you can put the screw back in the hole. If it hits something, remove the knob, remove the clutch and turn it 180 degrees. This will reposition the ears. Put the clutch back on the shaft, put the knob back on the shaft and screw the screw into the hole. Test to be sure the knob releases the hand wheel to wind the bobbin.Be sure the thread is under the thread guide when you wind the bobbin and that there is a slight tension on it.
sewman7

they were famous for that, because the screwpin that holds the eyepice shaft is metal and the groove that it rides in is plastic, and eventually gets jammed....look where you put your fingers to adjust eyepieces. should be small metal plate in center of hinge(sometimes with bushnell logo) that will simply pry off by using small screw driver,and now you will be able to see if the screw is loose or damaged. good [email protected]