Hello!

I have tried to convert an old marklin 3000 to digital, but with suprising results.

When I program it (using a SPROG 3 as programmmer (and as main control station due to tight budget)) it responds with little "clicks" as I have heard other people say they do when programmed. When I go to read it, it is unable to detect the loco and read ANY cv. At this point I think that I should just go with programming "blind" and try to run it.


As soon as the track power is on (tested and working) and throttle is applied to the correct DCC-address (factory default, 3) the decoder heats up very quickly, but it doesn't move the train. The motor is not stuck, and runs smoothly by hand. There is no voltage across the motor terminals when the throttle is full. It doesn't eaven move in analog DC operation... with the wires coupled directly to the cables of the decoder.

I have wired it like this fella: Pictures
He doesn't seem to have any problems at all...

EDIT: I have now tested the motor by applying voltage across its terminals, and it runs like a charm on even 5 volts.

Can anyone help me?

Best regards,
Oskar

Thanks for your quick answer!

After I ran the motor manually by applying voltage to the two terminals on it, the train now moves back and forth a little when reading and programming it (Read works now!). However the throttle doesn't let me run the train... The decoder just gets hot.

As for the graphite brush: I don't have one and don't know where to buy one more...
I still have the factory capacitor that sits between the tension springs, is that polarised (so that I should take into concideration the direction of currentflow through the motor)?

How should I install the two diodes? Two per side in both directions, totaling four? Two in total, allowing currentflow from the grey wire to the orange or the other way around? Could you send me a picture?

Thanks,
Oskar

Should I just try to install the cap without caring about direction? And try without the chokes?

you shouldn't try to run the loco until you've replaced the copper with a graphite brush, you will either ruin the decoder or the armature, I'm sure there will be someone on this forum near you who can send you a spare one (Webmaster) otherwise you can order it from Märklin direct .
the chokes go either side of the brush holder (1 each)

regards.,

John

Now it also gets hot with just the track power on, in other words the engine is off. The loco isn't even dialed in for operation. Is that normal?

That is what I had before (brushes)... And I have now changed back.

Right now it is wired without any chokes or capacitors. Will that work?

Is it normal that the decoder increases about 15 degrees Celsius after I turn on the track power and creep it forward for about 10 seconds (and idle for approx 4 minutes)?

Thanks!

believe me, you need 2 graphite brushes when converting a loco to digital. chokes are not used in analog mode only in digital conversions, capacitor is connected between the 2 brush holders usually on top of the brush plate.

regards.,

John

Is the choke critical? I don't seem to have one for this loco, the only one that I have is in a loco that I am not going to touch (since it is analog and part of a limited edition and could be worth something someday). Can I do this without one? I thought that I shouldn't have one since the manual for the decoder states that they (capacitors and chokes) might disturb the load control and should be removed (page 47, 11.3).

Regards,
Oskar

Thanks!

I bought three decoders and magnets from different places, but none of them came with chokes! Could there be another reason for why the decoder gets hot without the motor (and therefore the non-existing chokes) not being involved?

Regards,
Oskar

Oskar, the answer is no, the decoder shouldn't get hot without the chokes.
your question is a bit vague, does the decoder get hot without turning the loco on ?

the reason a decoder gets hot is for a motor not working properly, your loco has a 3 pole armature, maybe one of the wires is broken, maybe the 3 pole separation points are clogged up., nothing else.

as I've said before unless you've got a lok programmer to test the decoder we don't know if the decoder is ok, most probably the armature is at fault and by adding another carbon brush it may also help.

What is more or less the simplest conversion one can undertake you seem to have hit a stumbling block, the best thing is going back to the start and eliminate certain options. as mentioned in my posts. other wise we are going forward and backwards without getting your loco running again.

Tom, I can't remember where I've read it but it was obvious I've read it somewhere otherwise I wouldn't have changed all my locos to 2 carbon brushes.

regards.,

John

Oskar, when converting a loco to digital it is always recommended you clean the motor thoroughly, inspect the armature, cogwheels and especially dirt which most probably has accumulated over the years.

I've never taken the temperature (I'm not a doctor) , but I find it hot , mind you they tell you a decoder will heat up but to what temperature is unclear to me.
I'll find out on the ESU forum website and see what the comment is.


regards.,

John

Just checked as commented in your other post, but no significant difference in temperature was experienced.

You said earlier in the thread that it got hot when not moving, that is clearly not right. Try disconnecting the lights see if that helps, otherwise disconnect the motor completely so just the decoder is powered on. If it still gets hot when motor is not connected then the problem is probably somewhere else and not the motor. Is the covering on the decoder intact? No part of the decoder edges or where the wires join are rubbing on the metal bodywork? None of the wires as they leave the decoder (or anywhere else) are contorted such that the connections might bridge each other? There is no pinching of the wires that might have cut or damaged the cable?

I converted a logo early last month and every time I put the loco body on it would short out, turns out the loco boiler being metal was pressing against one of the chokes connected to the motor, so cover off it worked, cover on it didn't, caused me some head scratching as the problem wasn't immediately obvious.

I converted my 3000 just the other day but that was with Marklin 60760, however the Lokpilot v4 does appear to be vastly superior.

Hope you find out what the issue is, when you do please let us know.

Stu

I don't really understand the difference it makes, having two carbon brushes or not. Personally I doubt it would make such a huge difference to the temperature of the decoder if the those brushes were in reasonable condition.However it would appear that conversion kits etc prefer two carbon ones so it'd go with the advice that two carbon ones are better.

I'd really like to know the reason though rather than just be told it's the right thing. The copper ones also seemed a bit naff though as they lose their shape quite easily - is it that simple? I doubt it. Does anyone know why two carbons are better than one for digital conversions?

found out on the ESU forum, the decoders sometimes get even hotter than 45° C under load

regards.,

John

Thanks John! I really appreciate you asking and helping me so much!




This motor does not use more than one amp, as the current draw measured by a multimeter is not more than half an amp, with my hand pressing down the loco to create a load. Thanks tho.

Regards,
Oskar