Debugging Kato EM-13 install in GS-4

[nickelplate759]

I just got a new EM-13 decoder for a 1st-run Kato GS-4 (a bit behind the times, I know).  I can't get it to work and would like help debugging it.   

My DCC programmer (Sprog II w/ JMRI) just doesn't see the decoder at all.  The GS-4 (without the decoder) runs fine on DC.  It has had the 1st-run insulation retrofit kit applied.   I haven't smelled any evidence of escaping magic smoke.

My hunch is that the EM-13 isn't making good contact.  It looks like it needs to make contact on both its bottom and top sides.       It's pretty hard to test that once the whole thing is assembled.    Anyone ever debugged one of these? 

George

[victor miranda]

there are a lot of connections to inspect.

my memory is that the visual problem is sliding the decoder between the two
contacts in the tender.

I figured the loco would work if one missed that detail....
so you must have a different problem.

I'd start with connecting the decoder to a programming track and see if
the decoder responds.

then set it in place in the tender and see if it responds.

victor

[peteski]

A perfect thread for the DCC forum. 

The installation instructions ( https://www.katousa.com/cgi-bin/dl/dl.pl?dl.mif,EM13-Install.pd ) are a bit brief.
I agree with Victor that it is most likely a problem with contacts.  I have done that install couple of years ago and I seem to recall that (with all the metal strip contacts on both sides of the decoder) I might have had some problems too.  But I don't recall any specifics.

The decoder is IIRC made by Digitrax. It is set at short address 3 by default (as are all factory fresh decoders). Have you tried to run it using address 3?  Have you tried to run it on DC with the decoder installed?  I think the DC mode is enabled by default.

Since this is a motor-only decoders, there are only 4 connections: 2 on top and 2 on the bottom.  You're right, due to the design it is a bit difficult to troubleshoot.

[nickelplate759]

Perhaps someone will be kind enough to move it to the DCC forum   

I tried address 3 (short) - no joy.     I didn't try it with the decoder on straight DC.

Time to try some temporary leads I think, and test the decoder outside the engine. If that works I may solder on some jumpers to supplement the friction contacts.

George

[peteski]

Perhaps someone will be kind enough to move it to the DCC forum   

I tried address 3 (short) - no joy.     I didn't try it with the decoder on straight DC.

Time to try some temporary leads I think, and test the decoder outside the engine. If that works I may solder on some jumpers to supplement the friction contacts.

George

Soldering jumpers (and testing it outside of the model) might be the best way to approach this.  But if you have some small alligator clips you could try using those. Just put a piece of cardboard under one jaw of the alligator clip so that it only contacts one side of the board.

[nickelplate759]

I tried it with the decoder on DC (not DCC), and while the lights still work (to be expected, since they aren't wired through the decoder) nothing else does.

Putting the DC board back makes everything work fine on DC.

Just to make this complete - the GS-4 threw a traction tire while I was testing it.  Fun!
Time to call Kato I think.

George.

[nickelplate759]

With help from Kato the problem is resolved.  It was indeed a contact issue - the lower side of the EM13 was not making electrical contact with the bronze contact strips in the tender frame.   This was due to a very slight raised ridge around the edge of the contacts on the EM13 (apparently a manufacturing issue on some EM13s).  It isn't really visible, but you can feel the ridge with your fingernail.  I carefully filed the ridge off (but not the contact!), and everything works fine.

I could have achieved the same result by soldering jumpers between the EM13's lower contacts and the frame, but chose not to.

George