AO Series 10 Head problems -- Slideway assembly

por **Admin** Ter Nov 19, 2019 8:27 am

AO Series 10 Head

Sometimes the slideway assembly on the Series 10 head can become loose or have other problems (a scope I won from ebay suffered this problem). Eldred Spell offers the following tip:

"The adjustment on the series 10 head is very easy.

You just remove the plate over the thumb wheel (four small splined hex-drive screws -- Matt Brin advises using a Torx wrench (a T-6) as splined hex tools are hard to find and the T-6 is readily available and fits well) and loosen the four slotted screws on the same side as the thumb wheel.

Then, while pressing in on the piece under the screws (this takes out the play), retighten the screws. 'Should take under five minutes. If you have a really tight grip you might be able to make things bind. In that case, just loosen the screws and repeat with less grip."

Later, Eldred wrote: "I just realized that the instructions I gave you for tightening a loose series 10 head are slightly off. It's not necessary to remove the four small screws, but it is necessary to remove the main screws and open the head.

This is a little touchy because it opens the interior to dust and the thin lever that connects the two halves can get bent.

Having got that far, it is a simple matter of loosening the gib screws (one set on each side) , pressing the gibs in and retightening."

Matt Brin has kindly written an expanded procedure for this below:

1. AO scopes seem to have recessed seats for their machine screw heads that are slightly smaller than most flat screwdriver blades. I found a small craftsman screwdriver with a 4mm blade width to work well enough.

A slightly larger blade might be better (and slip less often), but the standard blade width of 6mm (or 1/4 inch) is just too big.

Read all of the rest first before starting, so that there are no surprises. All you need is the screwdriver mentioned in 1 above.

2. Remove eyepieces from their tubes and place them face up and out of the way on a clean surface.

3. Just below the point where the binoc/trinoc head joins the rest of the scope is the knurled screw that allows the head to turn. Loosen this screw two full turns and remove the head.

4. Set the adjustable tube to an intermediate setting (such as 5) and hold the head steady with the eyepiece tubes pointed down and resting on a clean surface.

The purpose of the intermediate setting on the focusable tube is so that the tubes lengths are approximately the same and the head is more or less level while you work on it.

5. Unscrew and remove the 4 screws holding the eyepiece tube assembly to the rest of the head. These are the screws whose heads are pointing straight up if you are holding the head as in 4.

Hold the eyepiece tube assembly tight to the rest of the head for the next step so that it doesn't slip around (or worse fall suddenly) since it is still connected to the rest of the head by an internal lever that is easily bent.

6. Place the head on a table with the entry lens (the lens that is not visible when the head is on the microscope) facing up. It will help if the head assembly is shimmed so that the eyepiece tubes are horizontal. With the trinoc head, this took 4 ordinary (thick) CD cases. With the binoc head, it might take only 3.

7. Carefully and slowly separate the eyepiece tube assembly from the rest of the head.

A lever connects the prism housing (part of the eyepiece tube assembly) to the entry lens assembly. The screw that attaches this lever to the prism housing should have its head facing up.

8. Note which hole in the prism housing the lever is attached to. On my assembly there are two holes.

9. There is a spacer under the lever where it attaches to the prism housing that will try to roll away when the screw is removed. Hold on to this spacer when loosening the screw.

Unscrew the screw holding the lever to the prism housing and put aside the screw and the spacer under the lever. The eyepiece tube assembly can now be handled safely.

10. Hold the eyepiece tube assembly with the the eyepiece tubes pointing down and resting on a clean surface. Turn the knurled dial so that the eyepieces are as close together as possible.

This is to make the next adjustment more reliable.

11. Each eyepiece tube rides between two rails (gibs?).

For each tube, one rail is integral with the assembly and one is adjustable.

The adjustable rail for one tube is held with 3 screws. Thus there are 6 screws in all. If only one eyepiece tube is loose, you only have to deal with three of them.

On my head, the three screws were loose for one side, accounting for the shift in the adjustable rail and the consequent play in the eyepiece tube.

12. Loosen the three screws for the rail to be adjusted about 1/2 turn each.

13. Hold the eyepiece tube assembly in a pinch grip with thumb and forefinger so that the adjustable rail is held tightly against the plate to which the eyepiece tube is attached.

Do not use more pressure than you can get with thumb and forefinger.

14. Turn the three screws holding the adjustable rail in place until they just barely seat, and then tighten them slowly by tightening each a small amount in succession and repeat as needed until they are quite tight. If you have an over tightening personality (such as mine) you will slip on one and remove a sliver of metal from the screw head.

Carefully get rid of the sliver so it does not fall into the scope and be more careful with the other screws. If you do this with two screws, your personality is even more tightly wound than mine.

15. Check the adjustment by (a) turning the knurled dial through its full range a few times to insure that there is no binding in any part of the range (there should be none if you only used finger pressure while holding in the adjustable rail), and (b) trying to wiggle each eyepiece tube while holding tight to the rest of the eyepiece tube assembly. Be careful of the prism housing while doing this. You can gently check the tightness of the screws on the other rail at this point if you did not need to adjust it.

16. Put the eyepiece tube assembly back on the stack of CD cases and re-attach the lever.

The spacer goes on the hole that you have remembered in the prism housing, the lever goes on the spacer, and the screw goes through both. Make the screw moderately tight. It should bottom out in its hole before it binds the lever.

The lever should turn freely under the screw head after tightening the screw.

17. Bring the two parts of the head back together so that the sides line up nicely and, while holding the two parts together tightly, return to the position with the eyepiece tubes pointing down and resting on a clean surface.

18. Replace the 4 machine screws that hold the two parts of the head together by first putting them in loose, and then tightening slowly as in 14 while holding the two parts of the head in alignment.

19. Replace the head on the microscope by tilting it in and tighten the knurled screw that holds it in place.

20. Replace the eyepieces.

att.

AO Series 10 Head problems -- Slideway assembly Prof_p13