Nikon MN-2 Battery Unit: Dirty job

An MD-4 motor drive with Ni-Cd battery pack MN-2 came to me.

As defective - the way I like it, because there is something to see and to do

The battery pack provides 16.8 volts for the motor.

Pretty strong.

Coincidentally, the associated service manual is available




Here the battery pack is inserted into the MD-4:




The connection contacts in the MD-4 are badly corroded.

There's definitely no more current flowing through it:




No wonder, because the contacts on the MN-2 don't look much better:






If I clean the contacts in the motor drive it might work again. With a battery holder for AA batteries, which is available as an alternative to the battery pack.

I could equip the battery pack with new batteries.

However, I am missing the associated charger. And nickel-cadmium batteries are already history. In addition, the casing is cracked

Let's see what it looks like in the MN-2.

14 cells that are interconnected.

Above this there are pressure strips made from the foam that rots sticky:




Some of the batteries have already entered the amorphous state

A process over decades:




Here are the contacts for the counterparts in the MD-4.

Everything soldered individually, the cables glued on.

A lot of manual work:




The rechargeable batteries have to go. There is no life here anymore:






An exhumation




The former operating data:




And the name:




An example of a series connection.

The sum of the individual voltages per battery results in the total voltage:




I would like to pick up the case of the MN-2. You don't see the battery pack that often.

I clean the parts in Durgol descaler solution.

The rest is hazardous waste:

The tools involved are cleaned of the sticky foam rubber residue using lighter fluid and a cotton swab:




As always, the work mat goes into the shower:




The cleansing bath did its job.

Where there were still greasy traces of foam rubber, lighter fluid and cotton swabs helped:




The MN-2 was reassembled and the broken parts were glued.

However, it is only used as a dummy, without any inner workings.

Ideal for teaching and training purposes






+++

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

Can you give me the schematic? I have recelled my MN-2 and it works great but I want to see what's the function of the diode. It seems like it's part of the charging circuit.

Chan Tran said:

Can you give me the schematic? I have recelled my MN-2 and it works great but I want to see what's the function of the diode. It seems like it's part of the charging circuit.

Click to expand...

I don't see any diode in the battery pack?

Andreas Thaler said:

I don't see any diode in the battery pack?

Click to expand...

my bad a resistor

Did you find a source for new batteries? I was lucky in that the last battery pack I re-did used AA sized Cadnica. So, I was able to replace with Eneloop batteries.

Chan Tran said:

my bad a resistor

Click to expand...

I'm sorry, but I couldn't find a resistor in the MN-2 either?

Andreas Thaler said:

I'm sorry, but I couldn't find a resistor in the MN-2 either?

Click to expand...

Well it's been a while since I have the pack apart. I replaced the cell with NiMH cells and they last much longer than the original cells. I still use the original charger but I think it may be better that I build a new charger that is better suited for the new type of cells. I thought there was a diode or resistor in the charging circuit but if not that's easy.

Eugen Mezei said:

Ni-Cd cells (with soldering fans) can be ordered in different sizes on Aliexpress. Replacing Ni-Cd with Ni-Mh/Eneloop is not a direct way.

Click to expand...

How did those no-name batteries work for you? Last time I used generic nicads they did not last long...waste of time.

Dirk Münchgesang on the German APHOG:

Christmas craft: Conversion of “Canon Ni-Cd Pack 1” into a battery holder for “Power Drive Boster PB-E1” (8xAAA NiMH)


Original version in German:



Translation into English by Google Translate:

Chan Tran said:

Well it's been a while since I have the pack apart. I replaced the cell with NiMH cells and they last much longer than the original cells. I still use the original charger but I think it may be better that I build a new charger that is better suited for the new type of cells. I thought there was a diode or resistor in the charging circuit but if not that's easy.

Click to expand...

Here exploded view and circuit of Nikon Quick Charger MH-2.

Is that what you are looking for?

That charger is one strange design. The 555 & 4040 counter seem to only be there as a 3.5hr timer for the D2 'charging' LED. And I have a feeling the schematic is wrong when it comes to 'Vcc.' One would think with all that electronics it would be sensing battery health and tapering the charge current - sadly the electronics does nothing so useful.

This sort of abortion of a design pops up when a mechanical engineer, with no electronics experience (How hard can it be?), is put in charge of electronics design. I would like to say that this never happens when an EE is put in charge of a mechanical design, but sadly no ('Stress riser, what's a stress riser.?).

Nicholas Lindan said:

That charger is one strange design. The 555 & 4040 counter seem to only be there as a 3.5hr timer for the D2 'charging' LED. And I have a feeling the schematic is wrong when it comes to 'Vcc.' One would think with all that electronics it would be sensing battery health and tapering the charge current - sadly the electronics does nothing so useful.

This sort of abortion of a design pops up when a mechanical engineer, with no electronics experience (How hard can it be?), is put in charge of electronics design. I would like to say that this never happens when an EE is put in charge of a mechanical design, but sadly no ('Stress riser, what's a stress riser.?).

Click to expand...

that is why I have the feeling that charger wouldn't fully charge my recelled pack with 900mAH cells.