Andreas Thaler
Subscriber
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:
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:
Last edited: