Narishige MO-102 Micromanipulator Repairs

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ldflan
Posts: 57
Joined: Sat Mar 11, 2017 5:05 pm

Narishige MO-102 Micromanipulator Repairs

Post by ldflan »

Hi, all.

I am looking for any guidance available on recharging the hydraulic fluid in an old Narishige MO-102. Like this one, but complete: https://www.ebay.com/p/Narishige-Type-M ... /557165728

Fluid smells like brake fluid, but if anyone knows specifically what was used, that would be most helpful.

Also, before I begin disassembly, I would be grateful for any input on procedures you might have.

Thanks!

ldflan
Posts: 57
Joined: Sat Mar 11, 2017 5:05 pm

Guidance for recharging Narishige MO-102

Post by ldflan »

Here is what I figured out.

You will need:

-Allen wrench (did not note size)
-Philips head screwdriver
-5.5mm open ended wrench
-3 to 5ml+ luer lock syringe
-Luer lock to 1mm ID 2mm OD PTFE tubing adapter, quick disconnect type
20ml or so of light machine oil (used Singer sewing machine oil; likely that any good mineral oil will work)

Procedure if not replacing PTFE tubing:

Remove the wrist / hand rest (allen head screws) and set aside.

Close the two large pressure-adjusting pistons all the way down to past 10 to the stopping point. Close the vertical adjust piston all the way down past 10 by turning joystick clockwise to stopping point.

Remove the Philips head screw from one of the pressure-adjusting pistons. This will open the bleeder for that line.

Remove one hydraulic line where it is attached to a servo. Push the colored collar and nut back up the line and out of the way. If your lines are damaged or need to be cut at the servo end, get a paper-clip and use it flare the end of the cut line, to make it easier to reattach to the nipple on the servo.

Attach the line to the empty syringe and suck all of the old oil out. Detach the syringe from the line and dispose of the oil.

Fill the syringe with new oil and evacuate the air. Re-attach the line you just emptied to the syringe and squirt new oil down the line. Watch the line and the bleeder. Stop filling when bubbles stop coming out of the bleeder, and the oil runs out clear. Replace the screw to the bleeder, being careful not to trap any air.

Now, while keeping light pressure on the syringe, open the pressure-adjusting valve from the fully closed position to well beyond the fully open position. Keep pressure on the syringe until it does not easily move any further.

Detach the line from the syringe. Re-attach the line to the servo, making sure that no air gets into the line. If it does, you can close the pressure-adjuster slightly until oil begins to seep out of the line again. This is the hardest part. Holding the line with a paper towel helps keep a grip on it.

Install the nut. Spin the pressure-adjusting piston control back to the scaled part of the barrel. By setting 1 or 2 the servo should start to move. If not, you can try re-pressurizing the line with the piston control backed all the way out.

Repeat with the other horizontal control line.

Re-charging the vertical control line is basically the same, except that you only have the one control (the joystick vertical adjust) to back off, so it's just one step to fill it, instead of two.

Good luck!

Leonard

Beatsy
Posts: 1652
Joined: Fri Jul 05, 2013 3:10 am
Location: Malvern, UK

Post by Beatsy »

Thanks for this post Leonard, extremely useful. I have two MO-202 manipulators, one of which has a couple of minor bubbles in the line. These bubbles don't appear to degrade operation in any way so I don't intend to do anything about it yet. But I was loathe to try undoing things anyway, in case something "irreversible" happened. Your post is very reassuring in showing the bleed and refill process is so straightforward should I decide to fix it in future. Thanks again.

ldflan
Posts: 57
Joined: Sat Mar 11, 2017 5:05 pm

Post by ldflan »

Welcome. I should mention this is a very messy process. Oil gets everywhere.

After 24 hours, I have two channels working fine. The third is slowly losing pressure, though I have not identified where. I strongly suspect it's the servo cartridge, but it could be the joystick piston cartridge. Will swap two servos and see if the leak continues in the same line or moves.

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