Nikon winder MD-E for the Nikon EM: Troubleshooting

[Andreas Thaler]

After taking care of my well-used and dirty Nikon EM

Nikon EM: Check and clean, issue with automatic shutdown of the exposure meter

The Nikon EM with its exclusive winder MD-E and the flash unit SB-E will be my next main project this year. With a focus on technical exploration, service and repair. Nikon EM: carefree photography The EM from 1979 was Nikon's attempt to make SLR photography accessible to customers with less...

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today I'm taking a look at the corresponding winder MD-E.

In a quick first test at the EM the winder doesn't work.

So let's take a closer look at it.

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The winder has obviously been used a lot and needs cleaning. The Nikon sticker was probably applied by the previous owner.

There is no corrosion in the battery compartment caused by leaked battery electrolyte.

This is good because the aggressive stuff spreads further through the cables to the circuit board and can cause damage there.

The contacts and springs must be cleaned in any case, as there is a coating on them.

The leatherette is also a candidate for cleaning. It is already peeling off a bit.

After treating the battery contacts with electronic cleaner, I put in the batteries and tested the motor function by short-circuiting the two contacts to the camera.

Since they were no longer shiny either, I polished them with the hard rubber attachment on the Dremel Stylo.

The instructions for this test can be found in the Nikon Service Manual for the MD-E, which I have in the original edition.

The motor should now start, but it doesn't move.

My first guess is that the springs in the battery compartment need more intensive cleaning than is possible from the outside.

So that's a reason to open the winder and remove the plate with the springs.

At the same time I can also check the condition of the gearbox and the electronics.

One of the cables to the two connection contacts is squished. This obviously happened during a previous assembly.

 

[Andreas Thaler]

Removal of the motor with gearbox and circuit board.

According to the imprint, the motor was manufactured on October 1, 1979.

The gearbox lubrication is used up. I will replace it.

Here is the back of the plate with the springs for the battery compartment and the red and black cables for the power supply.

And here are the connectors for the contacts to the camera, which I had previously short-circuited for testing purposes.

Now I can clean the springs thoroughly with the hard rubber attachment on the Dremel Stylo.

The contacts on the battery compartment cover also get this treatment.

I use the multimeter to check the continuity of the two cables. The yellow one also shows pinching.

The continuity is OK, ie the cables are conducting.

Nevertheless, I will replace them, as small damages in the insulation can divert current towards ground, which can affect the function of the circuit.

To narrow down the problem, I unsolder the plate with the springs so that I can connect the motor directly to my laboratory power supply.

If the motor and the associated electronics on the board now work, I need to continue looking in the battery compartment for the cause of the problem.

The motor is connected to a 9 volt operating voltage.

By short-circuiting the two contacts, it comes to life, rotates and the red control LED lights up.

I am relieved because further troubleshooting in the battery compartment is much easier than having to search in the circuit.

 

[Andreas Thaler]

I can put this unit aside for now.

Next, we look at the battery compartment and its battery connections.

I put the batteries in and measure only 2.7 volts at the compartment's output instead of 9 volts. So this is where the error lies.

I disassemble the battery compartment cover to check the mechanism of the on/off switch and clean all parts with electronic cleaner.

Here too, I measure the continuity with the multimeter and find that no current is flowing through the ON/OFF contact point.

The cause is a stubborn coating, which I remove with the fiberglass brush.

Now the 9 volts are present at the output of the battery compartment.

This should have solved the problem and the winder should work again.

In the next step I will replace the old lubrication and the two cables for the contacts to the camera.

Then clean and reassemble.

 

[Andreas Thaler]

Cleaning/lubricating the gearbox

A bath in Zippo lighter fluid to remove the old grease.

I recommend wearing a protective mask for this type of work, as the petrol fumes should not be inhaled.

Please also remember that petrol is highly flammable.

Clean

Remaining Zippo grease mixture is blown away with high-pressure air.

The result.

I only lightly grease the first gears, as the lubrication is distributed by the rotation of the gears.

I couldn't clean the gears here because I would have had to dismantle the housing to do so. But there is still lubrication that I can distribute.

The housing is now cleaned - done.


Cleaning the covers

New wiring

Old cables.

The new cables to the camera contacts and the battery compartment plate with the springs are soldered.

 

[Andreas Thaler]

The contact pins to the camera.

The sticker is removed with isopropyl alcohol.

Ready

And the joy is great when I mount the MD-E at the EM and everything works

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Conclusion

• The systematic troubleshooting with the multimeter was worth it, I was able to narrow down the problem quickly.
• This Nikon winder should not be underestimated either. It is solidly built and the plastic gears show no wear.
• Assembly was more difficult than expected. When inserting the motor unit into the housing, three components had to be aligned at the same time and the wiring of the LED was very tight. I almost lost my nerves

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At the end of the project, we will look at the Nikon SB-E electronic flash to see if it can complement the camera and winder duo.

Incidentally, I have already dissected an SB-E once:

Nikon Speedlight SB-E: Dissection

I was actually looking forward to the restoration of this little flash to the Nikon EM. Damage to battery acid in the battery compartment gave rise to hope for a major cleaning operation behind the battery contacts, with patching and soldering work on the circuit board. Externally in mint...

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+++

All information provided without guarantee and use at your own risk.

 

[4season]

Thank you for doing this! I don't know that there's any harm in using molybdenum grease on plastic gears, but I find it especially valuable in situations where metal rubs against metal.

Good luck servicing the SB-E strobe. Availability of oddly-shaped photoflash capacitors can sometimes be a challenge (short of special-ordering 1000x of the things), but perhaps suitable parts can be salvaged from a disposable camera, or sourced via AliExpress.

 

[Andreas Thaler]

Thank you for doing this!

You are welcome!

I don't know that there's any harm in using molybdenum grease on plastic gears, but I find it especially valuable in situations where metal rubs against metal.

There are always a few question marks.

Washing the plastic gears with Zippo, for example. I think the plastic can withstand it, as can the moly. Time will tell.

Good luck servicing the SB-E strobe. Availability of oddly-shaped photoflash capacitors can sometimes be a challenge (short of special-ordering 1000x of the things), but perhaps suitable parts can be salvaged from a disposable camera, or sourced via AliExpress.

Thanks, the hardest part will be opening the plastic casing, which is securely locked with clips. But I won't mess around too much, I'm wary of the high voltage.

 

[Andreas Thaler]

I found this:

So I asked Liqui Moly directly. The grease is compatible with the most common plastics and rubbers used in vehicle construction. Therefore, it can also be used in model making without any problems.

LM 47 Langzeitfett - RCForum.de

Hi allen, ich hab auf der Suche nach nem Schmierfett ne Tube Liqui Moly LM 47 MoS2-Langzeitfett gefunden. Auf der Verpackung steht leider nicht expliziet die Verträglichkeit mit verschiedenen Materialien drauf, ich zitiere mal: " Zur Montage, Wartung und Reparatur von Fahrzeugen, Werkzeugen...

www.rcforum.de

 

[Andreas Thaler]

According to the service manual, the motor should only run for 1.5 seconds after short-circuiting the two camera contacts. Here the motor runs continuously. Perhaps that is why a high-frequency noise can be heard when the shutter is released.

I'll look in the service manual to see if I can find any information about it.

There's not much I can do to the circuit anyway. The main part is in an IC, some tantalum capacitors, transistors, diodes, etc. are visible. I can check the components, but to do so I would have to remove the circuit board from the assembly and first disassemble the winder again. I don't really want to repeat that.

Since the winder works perfectly on the EM, I'll leave it at that.

 

[Andreas Thaler]

Here is further information in the service manual on the structure and function of the main switch in the battery compartment cover.

The figure at the bottom shows the ON/OFF contact.

If it is open, the multimeter shows high resistance; if it is closed, it shows low resistance (current does not flow or current flows).

This function can be checked with the continuity tester on the multimeter, which is what I did.

 

[ic-racer]

Nice work!

 

[Andreas Thaler]

Nice work!

Thanks!

 

[Andreas Thaler]

Another observation:

With the winder attached, the light meter does not switch off. Without a winder it takes longer than usual, or now the camera doesn't switch off at all.

But by setting the mode switch to M90 (mechanical shutter speed) the light meter can be switched off in both cases. That is then basically the main switch, which the EM lacks. When you tap the shutter release, the light meter switches on, which of course can also happen accidentally.

I can only imagine that a timer with a capacitor in the EM no longer works here.

I will try to get information about this.

 

[Andreas Thaler]

I found this:

LM 47 Langzeitfett - RCForum.de

Hi allen, ich hab auf der Suche nach nem Schmierfett ne Tube Liqui Moly LM 47 MoS2-Langzeitfett gefunden. Auf der Verpackung steht leider nicht expliziet die Verträglichkeit mit verschiedenen Materialien drauf, ich zitiere mal: " Zur Montage, Wartung und Reparatur von Fahrzeugen, Werkzeugen...

www.rcforum.de

Cleaning and lubricating plastic gears is a tricky thing.

I used lighter fluid and Moly Lube, both of which are more commonly used for metals.

The alternatives would be isopropyl alcohol and silicone grease, but I don't have the latter in my supply.

From everything I've read, lighter fluid and Moly shouldn't attack plastic. Since it's not known what kind of plastic the gears are made of (nylon?) and what their status will be after a lifespan of 45 years, it probably won't work without experimentation.

I will report back with my observations - in another 45 years

 

[Andreas Thaler]

See also

Nikon Speedlight SB-E for the Nikon EM: disassembling, clean/replace corroded battery contacts, check

As the third and final sub-project in my Nikon EM series, I will try to get a small SB-E system flash for the EM up and running again. In the battery compartment, there is severe corrosion of the contact springs due to leaked battery electrolyte. This is probably the most common error with...

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