Hi Folks,

I have come here with desperation. Please help me. I bought a Marklin 4000 Big Boy (37990). I have a mobile controller (60657). I got the loco running by searching the database in the controller. I selected 37990 Big Boy and it immediately started working. All the functions responds. The lights and the sounds. HOWEVER: the volume is so low that one can only hear it when putting your ear next to the tender. I cannot get the volume up. The controller does not allow me to turn it up either. I know it is a pre-mfx loco. How do I get the sound volume up? I even opened the tender as a final resort and fiddled with switches 9 & 0, without any success. I must be missing something, it can't be that difficult to set the volume. Any ideas or advice?

Thank You!

Hi KiwiAlan,

Thanks for the advice. I am not quite sure I know how to go about doing it.

Thanks

37990 has two decoders – one in the loc, one in the tender. The decoder in the loc has two potentiometers, for setting max speed and acceleration/breaking delay, respectively; the one in the tender has one potentiometer, for setting sound volume. The latter should enable you to set the volume to your desired level.

Jeroen

Folks,

Thank you for helping. How does one set the potentiometer within the tender decoder?

Thank You!

A fine flat blade screwdriver will work fine. If you have the Marklin Toolkit then the smaller flat blade driver in there will do fine.

That was only for purchasing it, as it was an Insider model. Anybody can get the manual on that page that is linked to above, but your loco should have a manual with it in the box.

There are people who have done this, but I have no experience of doing so. I'm guessing that Marklin have a Big Boy sound schedule for their decoders, I know that ESU definitely do, and I believe theirs is quite impressive.

Folks, I am by no means an expert. I have not cleaned mechanics nor inspected wires. However, I live in the middle of the desert. The closest Märklin specialists are in Capetown (1000km away) and Johannesburg (600km). Can this problem be solved by my own hand?

With regards to dip switch 9 on p47 of the manual: i have taken off the tender top and adjusted the 9 switch first, without any effect, and then also switch 0, also without any effect.

Yes - definitely clean the signal generator, which is located on an axle in the front engine. That is an area where excess oil tends to accumulate and in my experience that will cause sound problems.

Ultimately I think that mine should get new, up to date electronics to run and sound its best. I do digital upgrades and conversions but that is one loco I am concerned about upgrading, because it is pretty complex with the various circuits and two decoders. Mine is working fine for the moment and if/when I decide to update it I will most likely seek out a professional to do that work.