can't get your your pictures

I could not access the first two photos either.

Sometimes, the decoder shorts internally and this causes the decoder to fry, usually quickly. Other times, wiring short circuits can cause excess voltage to be carried by wires to circuits and resistors that were not designed for that much power, which can cause heat and even fire.

In order to determine where the problem occurred, a photo of the circuit board and decoder with the tender cover removed would be helpful.

If the lok was delivered from the factory with the decoder and is still within it's 12 or 24 month warranty period, you should contact your dealer, distributor or Maerklin or other manufacturer as the case may be. If the lok happens to be under warranty, you may not want to tamper with it before you send it in for repairs or replacement. If the lok is outside it's warranty period, or if the decoder was installed by you, you may have to pay for repairs on your own. If the decoder was new, you may have a claim based on the decoder's own warranty. Check with the decoder manufacturer for more precise information.

Oh, it is supposed to be "cook until tender" and not "cook your tender". Hope a little levity makes you smile for a minute. Good luck with the repairs.

MC

Greg, Sorry about loco.
Photos cannot be seen as there is a Gap in the title eg photo 1.jpg.

Take out the gap and reload. or use the feature to attach photos to your post.
Nev

I'm sorry Nev, I just can't seem to get the photos to display. I tried the adjustment as you suggested, but no difference.

Sorry for the late response - I've been watching the football final on TV. The Sydney team beat the NZ team.

Just playing trains with my grandson.

The loco is the 29010. I bought it 2nd hand so there's no claim - I can live with that - I've always had this kind of luck. I'm the next best thing to Murphy's law.

I've uploaded the 3 photos into "My Album" titled "Fried Decoder". Is this all I have to do ? I think my brain has been fried as well as the decoder

Thanks Robert for the explanation. I just have to be more careful when I'm operating the trains.

For everyone - I'm going away for a few days and I won't be near a computer. so please forgive if I don't reply during this time.

Regards
Greg

My 29010 went back to Märklin for a warranty repair - there was a contact problem on the PCB inside the loco (one of the printed circuits was broken).
I wonder if a similar defect could be the problem here - a not completely broken printed circuit will have a higher resistance. Or maybe it was completely broken and making contact with a different circuit.

Re: inserting pictures:
Do not insert blanks after ".jpg". Make sure all characters (including spaces) in the filename are exactly as the file you uploaded.

These are the filenames that work (pictures can be seen in post #3):

Hi Tom,

I have only one hypothesis:

I see the more burns are in correspondence to the 21 pole connector and the electronic components are not deformed like it is, so maybe the problem is underside the upper PCB or in the connections between the upper and lower PCBs.
I think that in case of a motor overload or short circuit, the integrated circuits powering the motor should be burnt and blown (and they are not, but the 21 connector yes).
I should have a look at the lower PCB anyway.

Cheers

Renato

Interesting photos, must have been quite a fire in there!

During debug of my own homemade decoder I experienced some fires of diodes and MOSFET motordrivers that burned through (bad design of my part). They gave a short intense flame, but were not able to burn through plastic. My central station (ecos1) did always go into short circuit protection when that happened.

I guess your 21 pin connector caught fire and kept burning for a while. I agree with Renato, it is not caused by the motor, you can see the MOSFET motor driving ICs (the 8pin ICs) next to the 21 pin connector.

My suspect would be the tantalum capacitor on the bottom of the PCB. It is usually a yellow or black brick-shaped component. They are known to be very sensitive to over-voltage and temperature, and occasionally go up in smoke with lots of fire when mishandled. Possible causes in this case:
- it could be that the booster input transformer gives too high a voltage. (do not use blue transformers!)
- are your seperate booster sections split up as required? If another train was just crossing 2 sections and connecting them with its slider it is very well possible a short voltage spike was present on the track with your steamer stressing the cap.
- bad batch of capacitors used for the decoder, or they were stressed during decoder assembly (too high temperature)

Funny experience with the tantalum capacitor I had: at my work (I'm an electronics engineer) I have known engineers running away from our lab in a complete panic looking for a fire extinguisher because one of the capacitors caught fire. The thought the building was going up in flames :). The lab was full of smoke and the PCB (eurosize) was entirely black. And that was a similar cap as is (was) in your loco.

Bert

I think you should send these pics to Märklin Service department - service@maerklin.de - and ask why this could happen...

Hi all,

Here are some pictures of what bad contacts can do:




In the 3rd picture the blue (neutral) wire together with its connector completely came off the PCB.

My company works with HVAC controls and we see this sort of damage from time to time, these pics happened to still be on my home laptop, we have other pics showing more severe damage.

The extend of the damage depends on how long it took for this process to get to the point where the control stopped working. Also small currents can cause such damage, it all depends on how much heat is accumulated during the process. Remember that a light bulb filament in that loco reaches some 2500 deg. C and more with only a handful of milliamps at 16Volts.

Obviously heat accumulated much more easily in the confined space of that tender than in the devices shown on the pics above.

As for tantalum caps and other electrolytic capacitors, yes they can explode and give off flames, but the heat damage is usually a lot less extensive because of the very short time the flames are present. it takes a couple of minutes for that connector to get heated up to the point where it deforms the way it did. That is not caused by burning plastic but by the plastic melting away. These 21 pole connectors are regular PCB connectors, made of self-extinguishing material, or so they should be.

Regards, Robert

I don't see any pictures.

Dennis, I have sent Greg an email letting him know I have a decoder out of Marklin 37881 that would do the trick to get him up & running again. The Sound option is infinitely a more expensive option but easy to do if he wants it so. The tender is a Göppingen only order.I could find nothing on E-Bay DE with regards to a second hand tender for that model. Anyone got any other ideas to help Greg out of this shocking demise?

Hi everyone,

After all this time I accidentally found the reason for the decoder "frying". It was all my fault. I have 2 tables which are isolated electrically with one table powered by the CS2 and the other by a booster. Doing some track/layout maintenance, I forgot to put the isolation back in one section and so the table with the booster was powered to 40 volts. I tested the track with a multimeter and that was the reading. All I can say is that I was lucky to lose only one loco. Next time I'll be more careful and hopefully my experience will save someone else from this disaster.

I'm starting to lose count of all my "dummy" actions.

Regards
Greg

Hi Greg
well not a great sight, but its looks fixable So I turned up
the parts sheets and found as follows.
now the tender cover is part 49 no 126065 and available from Germany
and the decoder is part 54 126070 and the base part 55 126069
which begs the question would it simplier to replace the who decoder with
an ESU sound decoder
so if you want some help we could get the parts from Germany for you
as I don't think the tender cover would be in stock here, But Dion
could have a replacement decoder
The other main cause of decoder fry is Digital locos on Analogue controllers
and the Reverse button held down to long giving 23Volts which decoders don't like
Advise
Bryan Toottoot chch NZ