Lego power function motors lost power

[Matajen]

I have an old Lego Technic set (8043) that has been standing and collecting dust for many years. When I tried to power it up it turns out that the motors have lost power. Of course I put in new high quality batteries. I also disassembled the model and rebuilt it but still doesn’t work. To be clear the remote and the motors work properly, but they have become so weak that they lack the power to make the model move. I have searched this forum and others to find an explanation and possibly a remedy, but so far with no success. Does anyone here has any advice to offer?

[aFrInaTi0n]

As those are brushed motors exactly those may be in a weared out state.
Except this idea, I unfortunately can't really help any further.. if it is the brushes, then exchanging only them wont make sense - only way I could think of is opening it and replacing the motor itself. But then you may have a damaged plastic housing.

Have you put them out and tested them separately (against another power source)? If all are affected, then it may be the battery box..

[Jurss]

Check all contacts, maybe they are "coroded". maybe just needs to be cleanded. Maybe the same happened really inside of motor - the collector is coroded. Then You could just try to run it free for some time, it could clean up by it self.

[Matajen]

12 hours ago, aFrInaTi0n said:

As those are brushed motors exactly those may be in a weared out state.
Except this idea, I unfortunately can't really help any further.. if it is the brushes, then exchanging only them wont make sense - only way I could think of is opening it and replacing the motor itself. But then you may have a damaged plastic housing.

Have you put them out and tested them separately (against another power source)? If all are affected, then it may be the battery box..

They seem all to be equally affected. Would be interesting to try a different box, even if it seems strange that the box could deteriorate upon storage. I have another model (Unimog) and see a bit of the same but not as bad. They are more or less the same age.

2 minutes ago, Jurss said:

Check all contacts, maybe they are "coroded". maybe just needs to be cleanded. Maybe the same happened really inside of motor - the collector is coroded. Then You could just try to run it free for some time, it could clean up by it self.

I've let all motors run free for at least 30 min, but still doesn’t help. Will try electric contact spray on all contacts from the battery box.

[aFrInaTi0n]

2 hours ago, Matajen said:

I've let all motors run free for at least 30 min, but still doesn’t help. Will try electric contact spray on all contacts from the battery box.

That would have been my next idea. good luck with that!

[Matajen]

I cleaned all the contacts and it works well now! Amazing, it was nothing wrong with the motors. Many thanks for your advice!