That's complete baloney!

The current coming out of a CS2 / CS3 is neither AC nor DC, this has been discussed in the forum quite a bit. The signal is more like a square wave when you look at it on an oscilloscope.



That's even more baloney and these so called clever modellers have no idea what they are talking about.

The 74490 / 74491 motors fail because the contacts in the micro switch at each end wear out, i.e. the problem is a mechanical failure not an electrical one as they seem to imply. This is why the motors will often fail to work in one direction but still work in the other direction. The switches are there to provide overload cutoff of power to the solenoid. The solenoids themselves are usually fine. You have probably repaired your point motors by solder bridging the contacts on the switches, and while this works it removes any overload cutoff protection.

In my opinion the proper fix is to remove the switches and replace them with an inline re-settable fuse. These look like a ceramic capacitor but are actual fuses. I have done this with several point motors and they work fine.

In the Word document I've attached to this post there is a translated copy of an article originally written in German - link to it is in the Word doc.

I used re-settable fuses I got off Aliexpress, but the specs required are listed in the document.

https://www.aliexpress.c...2%3A%2262393914869%22%7D

Be careful when desoldering the switches as it is all too easy to lift the PCB track off the circuit board.

Replacement of the Marklin 74490 and 74491 limit switches with resettables PTC fuses.docx (60kb) downloaded 74 time(s).

The issues with the point motors has previously been discussed in

https://www.marklin-user...lin-74490-turnout-motors

and

https://www.marklin-user...urnout-Motors-74990.aspx

Do you have any manufacture of these fuses or do you have a simple description how to fix it?
As you understand, I need advise from a person Who knows. If you have, I can also give you my email adress

Thank you once again.
Regarding 60822, when is this absolutely needed?

Only you can decide that, but the decision should be based on what I said.

I don't have an M83 units but do have Viessmann 5211 decoders which are capable of being powered by a separate transformer. They only need the track output power to receive the digital commands and the decoder itself is powered from the separate transformer - that's how my setup works.

If you have a reasonably medium to large sized layout it would be better to start off with the M83's powered by a 60822.

The fault with the original 74490 and 91 was the microswitch failure due to contact arcing when they disconectd the coil at travel end. Seems the electrical engineers at Marklin never cosidered this in the design and implementation. I repaired all of mine manu years back and have never had a problem.
1) With the failed ones I replace the micro switch and soldered a 0.33 MFD 100 volt SMD capacitor beween the micro switch leads.
2) With the still working ones I just added the capacitor.
3) for all I added 0.1MFD axial capacitor across each coil.

Have not had a problem since.

What actualy happens is the collapse of the magnetic field induces an electric current in the coil as the micro switch opens. This causes arcing, which after a a number of operations deposits enough carbon on the contacts to increase the resistance to the point where no enough current flows to energize the coil.

I have the instructions somewhere if its of interest I'll try to find it. I sent it of to the Markilin digital guys a few years back as they also discussed this.

Hi, I am hoping you may be able to tell me what I am doing wrong.
My layout is controlled by a CS3+ with a CS2 as a slave. I am trying to test a couple of Viessmann 5211 decoders. I have set the codes to vacant codes, but I can’t get my CS3+ to talk to them. All other decoders are M83s

Any thoughts?
Thanks
Adrian