Hello everyone! I own an old CM800 in pretty good shape that I want to upgrade. My goal is to install a digital decoder together with a permanent magnet and a 5 pole anchor. If it goes well I might upgrade the lights to LEDs and also add lights in the rear of the loco. I'll also make sure to do the usual service as changing the brushes, the rubber rings and also the center rail pickup since it is quite worn.

The list of parts I've come up with looks like this so far:
60943 Conversion kit
7154 Traction rings
7185 Rail pickup
600300 Brushes

As a decoder I think a ESU 54610 (Lok-pilot v5) will do. I've used in another locomotive and i
t seems enough for my needs.

So far I have taken apart and serviced a handful of Märklin engines but this will be the first one I switch any parts on. Since I am familiar with both general mechanics maintenance and electronics I think I'll be able to pull it off. I'm however not sure that the parts I've found are the correct ones. I assume by the look of my motor that it is a Small Flat commutator motor, and that I therefore should use the 60943-kit. Anyone who could shed some light on this? Also, do you have any other tips or tricks when doing a project like this? :)

Happy new years and best regards,
Filip

Hello Filip

I may be able to help as I completed this upgrade myself a few weeks ago.

I upgraded the loco as it has significant sentimental value being my first loco which I received for Christmas about 1965.

The table in the CS3 manual lists the appropriate conversion motor as 60943 which is what I used. Marklin say that to do the conversion you should send it back to Marklin.

This for me was not an option as postage to Germany and Back to Australia would be more that the loco is worth so I ordered the parts. I also used the Marklin 60972 decoder.



There is one hitch to the upgrade. With the new motor they provide new screws. The heads on the screws are bigger than the old ones and when put in foul the rear wheel. My first solution was to find where to file a flat on the head o the screw so as it would not foul the wheel. See attached photo where the tip of the screwdriver is.



This went fine but when I put the screw in it was too long and when right through the casing and stopped the cogs on the other side of the loco from turning. I did not want to cut the screw for fear of burring the thread. My ultimate solution which would have overcome the need to file a flat on the head of the screw was to make a spacer that would not foul the wheel and would keep the head of the screw from fouling the wheel. This worked a treat and the Loco lives on after some 55 years.



I hope this helps

Michael

Hello again Filip

Reading what I have said you are probably going to ask why I did not use the original screws with the smaller heads. I tried this but they ae too short for the new motor.

Regards



Michael