Hi,

I have installed a couple of ESU power packs 54671 with positive results.

One thing I never liked however is the fact that it required soldering onto the pads of the decoder. If you follow the instructions, the three wires should go on three pads on the decoder and that is what I obediently did before I knew better.


Instructions in the manual



Soldering directly on the decoder board never gave me a good feeling:
- Chance of ruining the decoder and destroying the warranty
- Impossible to remove/exchange the decoder without desoldering the wires
The ESU decoders come with the speaker wires soldered to them as well, so that would make 5 wires fixed to the decoder.

I then realised that 4 of the 5 wires can be connected to the MTC21 board instead of the decoder board.
The speaker wires go to Pin 9 and 10.
The black wire of the power pack is GND and goes to Pin 20
The red wire of the power pack is U+ and goes to Pin 16 (the orange wire)



What was left was the white wire connected to Aux9, which has no MTC21 pin associated with it.
The function of power pack controller can however be allocated to another function output, which does have a MTC21 pin.

I chose Aux5 for this role, so the white wire could now go to the MTC board on Pin 17.


The only thing left to do is to program the decoder to give the Aux5 output the role of Power pack control. That can be done in the Lokprogrammer menu.



Now all 5 wires can be soldered to the MTC21 board, which cost a few € instead of the expensive ESU decoder. The decoder remains untouched and can be easily taken out.

Best regards,
Gregor

Connecting an ESU power pack to a Märklin decoder is not straightforward. Märklin has 4 wires between it's power pack and the SUSI interface on the decoder board. ESU uses 3 wires to connect to U+ (orange), GND (violet) and a function output on logiclevel. You could connect it like this to a Märklin decoder as well, and switch the power pack on yourself through a function key, but then it would be constantly on. I do not know how that may affect proper operation/overload etc.