Condenser is loose fitting in Leitz LM Lux

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Andy-ross
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Joined: Fri Dec 15, 2017 9:48 am

Condenser is loose fitting in Leitz LM Lux

#1 Post by Andy-ross » Fri Dec 15, 2017 11:05 am

Hello folks, a new member here.

I recently got myself an LM Lux with a Phase Contrast condenser and objectives.

There seems to be a problem with the dovetail for the condenser.
It seems to be too slack, the condenser just rattles from side to side when I make adjustments and it slides backwards and forwards , if I tip the stand forwards it falls out altogether.

Is there any way to tighten the dovetail?
I can see that the tops of the two rails are held in place by machine screws and I am wondering if they can be tightened, If they can how do I get in atthem as the space between the stage and the dovetail is too narrow to allow a screwdriver to get in.
Is there a way to remove the dovetail fitting to allow me to work on it?

Thanks in advance.

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mrsonchus
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Re: Condenser is loose fitting in Leitz LM Lux

#2 Post by mrsonchus » Fri Dec 15, 2017 11:32 am

Andy-ross wrote:Hello folks, a new member here.

I recently got myself an LM Lux with a Phase Contrast condenser and objectives.

There seems to be a problem with the dovetail for the condenser.
It seems to be too slack, the condenser just rattles from side to side when I make adjustments and it slides backwards and forwards , if I tip the stand forwards it falls out altogether.

Is there any way to tighten the dovetail?
I can see that the tops of the two rails are held in place by machine screws and I am wondering if they can be tightened, If they can how do I get in atthem as the space between the stage and the dovetail is too narrow to allow a screwdriver to get in.
Is there a way to remove the dovetail fitting to allow me to work on it?

Thanks in advance.
First check - you may very well have the condenser 'on top of' the actual dovetail grooves in the holder - the condenser appears to slide in normally but is bizarrely loose and is difficult to focus the field iris too! Check you are indeed sliding the condenser into the actual slots - it can be a little stiff to push in but that just ensures a good fit...
John B

Andy-ross
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Re: Condenser is loose fitting in Leitz LM Lux

#3 Post by Andy-ross » Fri Dec 15, 2017 11:42 am

Thanks for the reply. The condenser is definitely in the grooves, it doesn't move up and down, just wobbles slightly and won't stay all the way home.

Charles
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Re: Condenser is loose fitting in Leitz LM Lux

#4 Post by Charles » Fri Dec 15, 2017 3:53 pm

You can get to the top of the condenser holder screws by removing the stage or sliding the condenser holder down and off. You may need to remove the light housing and there is a screw on the condenser holder which needs to be loosened. The screw end runs along a groove which keeps the condenser holder from dropping down off the rail.

MicroBob
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Re: Condenser is loose fitting in Leitz LM Lux

#5 Post by MicroBob » Fri Dec 15, 2017 5:51 pm

Hi Andy,
I don't know this microscope but a sliding dovetail should have the same width front and back. Do you have access and a measuring tool to check this? It might have been forced apart in the past when a condensor became stuck from gummed up immersion oil.

Bob

Andy-ross
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Re: Condenser is loose fitting in Leitz LM Lux

#6 Post by Andy-ross » Fri Dec 15, 2017 6:10 pm

MicroBob wrote:Hi Andy,
I don't know this microscope but a sliding dovetail should have the same width front and back. Do you have access and a measuring tool to check this? It might have been forced apart in the past when a condensor became stuck from gummed up immersion oil.

Bob
Could be, I have a vernier, I will check.

Andy-ross
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Re: Condenser is loose fitting in Leitz LM Lux

#7 Post by Andy-ross » Fri Dec 15, 2017 6:11 pm

Charles wrote:You can get to the top of the condenser holder screws by removing the stage or sliding the condenser holder down and off. You may need to remove the light housing and there is a screw on the condenser holder which needs to be loosened. The screw end runs along a groove which keeps the condenser holder from dropping down off the rail.
I see the screw and when the holder is racked down I can see the groove.
I removed the screw from the front but the housing still comes up against a hard stop at the bottom of its travel.

MicroBob
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Re: Condenser is loose fitting in Leitz LM Lux

#8 Post by MicroBob » Fri Dec 15, 2017 6:21 pm

Can you post a picture of the situation?

Andy-ross
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Re: Condenser is loose fitting in Leitz LM Lux

#9 Post by Andy-ross » Fri Dec 15, 2017 6:50 pm

Right, progress.
I removed the stage (a job in itself, two allen screws one each side, with knurled heads so when they were slackened by the key I could finish them off with fingers)
But it was still held somewhere. Investigation shows another allen screw in the middle with it's head showing just above the substage holder, with this at its lowest setting I could get in and loosen the screw off.
With the stage removed I got in to the problem area.
The dovetail is formed by two 'wedge' plates bolted to the top of the carrier. One of them is supposed to be spring loaded and able to move a mm or so to put pressure on the condenser slide.
This part was seized up and solid with old grease so it wasn't putting any pressure on to the carrier.
Now it is all cleaned and able to slide and put pressure on everything is working as it should :)

Andy-ross
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Re: Condenser is loose fitting in Leitz LM Lux

#10 Post by Andy-ross » Fri Dec 15, 2017 7:44 pm

Working OK, I can align the The phase contrast annuli in the condenese with rings in the objectives using the telescope but the iris on top of the lamp seems to be out of alignment. I can't see any way to move the lamp itself.
I notice the base of the microscope is seperate to the column and they are held together with 4 allen headed bolts accessed through the base when the bottom cover is taken off.

Would I be right in thinking the allignemnt of the base with the lamp and the column needs a small adjustment?

Charles
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Re: Condenser is loose fitting in Leitz LM Lux

#11 Post by Charles » Fri Dec 15, 2017 9:23 pm

I wouldn't mess with the four screws attaching the base to the limb. You should first set your microscope up for Kohler illumination. I suspect your are using the condenser alignment screws to use to align the phase annuli of the condenser with the objective. You should use the two condenser alignment screws to properly position the condenser for Kohler illumination. To align the phase condenser annuli to the objective phase places, you need special phase alignment tools, with a square drive, which is inserted on both sides in the back of the condenser. These are small square drives which are inserted and turned to adjust the position of the phase annuli in the condenser. A picture would be helpful.

Andy-ross
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Re: Condenser is loose fitting in Leitz LM Lux

#12 Post by Andy-ross » Fri Dec 15, 2017 10:08 pm

Charles wrote:I wouldn't mess with the four screws attaching the base to the limb. You should first set your microscope up for Kohler illumination. I suspect your are using the condenser alignment screws to use to align the phase annuli of the condenser with the objective. You should use the two condenser alignment screws to properly position the condenser for Kohler illumination. To align the phase condenser annuli to the objective phase places, you need special phase alignment tools, with a square drive, which is inserted on both sides in the back of the condenser. These are small square drives which are inserted and turned to adjust the position of the phase annuli in the condenser. A picture would be helpful.

I see the square ended adjusters in the disk, there are holes in the assembly to allow access to whichever one is under the objective. I suppose there is a special Leitz tool for this job?

Andy-ross
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Joined: Fri Dec 15, 2017 9:48 am

Re: Condenser is loose fitting in Leitz LM Lux

#13 Post by Andy-ross » Fri Dec 15, 2017 10:24 pm

Al luck has it one of my hobbies is repairing old pocket watch movements. I have loads of winder keys, they are square sockets, I have a couple that fit and just had a go at one of the number 1 ring and it came in perfectly.

What a great forum this is.

Andy-ross
Posts: 13
Joined: Fri Dec 15, 2017 9:48 am

Re: Condenser is loose fitting in Leitz LM Lux

#14 Post by Andy-ross » Fri Dec 15, 2017 10:57 pm

Thanks folks. your replies put me on the right track and gave me the confidence to have a go.
Everything lines up beautifully now.

Charles
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Re: Condenser is loose fitting in Leitz LM Lux

#15 Post by Charles » Fri Dec 15, 2017 11:13 pm

Glad everything is coming together!

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