Help with TCS MC4

[StewRRFan]

TCS MC4 installed in a Kato GS4.  I did not do the install.  Above my pay grade.  Engine is non responsive either on live rail or on the programming track.  Suggestions to see if this is a reset issue (and how) or if the decoder is just bad.  Thanks for any assistance. - Ross

[conrad]

TCS MC4 installed in a Kato GS4.  I did not do the install.  Above my pay grade.  Engine is non responsive either on live rail or on the programming track.  Suggestions to see if this is a reset issue (and how) or if the decoder is just bad.  Thanks for any assistance. - Ross

Generally speaking, the DCC guru's need more info for an analysis.

For example: What command station and throttle are you using?  Did the loco run prior to the decoder install?  Are the tracks clean?  Does "non responsive" mean dead dead or are there light flashes or a momentary motor cog?  Can you read the address?  Have other DCC loco's run on your system?  Have you tried an "on the main" decoder reset?  Etc, etc.

A history of the install would be helpful also.

The more info the better.  This thread has many, many years of knowledge and experience with everyone very willing to help.

Conrad

[StewRRFan]

Good points Conrad

• What command station and throttle are you using?  Digitrax PS3 stand alone programming and Digitrax 51 command station with another programming track.  No response on either.  Will not read
  Did the loco run prior to the decoder install?  Yes.  As DC and DCC
  Are the tracks clean? Of course
  Does "non responsive" mean dead dead or are there light flashes or a momentary motor cog?  Nothing.  No lights, no motor cog
  Can you read the address? No
  Have other DCC loco's run on your system? Yes
  Will not respond on DC either.
  Have you tried an "on the main" decoder reset?  Can not get a read to reset.

At this point, I am guessing it is fried.



A history of the install would be helpful also.

[Steveruger45]

Power pickup from the track ok?

[StewRRFan]

It does not seem I am picking any thing up from the track.  Programming and DC tracks checked for power.

[Steveruger45]

Ok, then if the track is powered ok then seems like no power is getting to the decoder and the loco is not picking it up. suggest check the wheels and wipers are making good contact.

[nickelplate759]

Another idea - I believe the MC4 has a plug in harness.  If you have access to another, working, locomotive with the same kind of harness you could plug your MC4 into that loco.  I wouldn't try it the other way 'round, in case your loco has a short somewhere - don't want to toast that decoder if you can help it.

[StewRRFan]

Thank you all so far.  The wipers are getting power when on the DC Test track.  Removed the weight from the tender.  Wires all look to be connected.  Picture below

This is the only engine I have with a hard wired decoder so no way to swap it out.

[StewRRFan]

With more research, I am wonder if i have a 1st version that had the issues with the short.  There is a spacer kit to correct this but I cant really tell if these are installed.  It is SP 4431.

[peteski]

With more research, I am wonder if i have a 1st version that had the issues with the short.  There is a spacer kit to correct this but I cant really tell if these are installed.  It is SP 4431.

Interesting hypothesis. The spacers were installed between the 2 rear drivers (#3 and 4) and the chassis.  It was a thin clear plastic shape.
The subsequent runs had their upper frame (the frame that retains the motor) modified to increase the gap between the frame and drear 2 drivers.

See https://www.katousa.com/N/GS-4/maint/GS-4spacer.html

[StewRRFan]

No spacers and it this is the 126-0303 version which appears to not be the 1st run with the short issue.  I guess I'll pick up a new decoder and see what happens. 

[peteski]

I'm not a big fan of the way Kato designed that power pickup scheme (for plug-n-play decoder functionality).  I also see that the person who installed the decoder did not depend on the drawbar motor connection and hardwired the motor and headlight.  Probably a good idea in the long run.

But I'm still worried that the rail pickup strips might not be in good contact with the dummy decoder plug which has the red and black wires soldered to it.  Do you have some jumper leads with alligator clips on them?  If you do, try to clip the leads to contact the red and black wires, then clip the other end of the jumpers to the track. Pull the dummy decoder circuit board out of the tender if that will make it easier to clip the jumpers to it. That will guarantee a solid power connection to the decoder.  Then see if your DCC system sees the decoder.

[Steveruger45]

I'm not a big fan of the way Kato designed that power pickup scheme (for plug-n-play decoder functionality).  I also see that the person who installed the decoder did not depend on the drawbar motor connection and hardwired the motor and headlight.  Probably a good idea in the long run.

But I'm still worried that the rail pickup strips might not be in good contact with the dummy decoder plug which has the red and black wires soldered to it.  Do you have some jumper leads with alligator clips on them?  If you do, try to clip the leads to contact the red and black wires, then clip the other end of the jumpers to the track. Pull the dummy decoder circuit board out of the tender if that will make it easier to clip the jumpers to it. That will guarantee a solid power connection to the decoder.  Then see if your DCC system sees the decoder.

Yes, This ^^^^^^.    I was thinking exactly the same thing Pete.
I’ve actually removed decoders and wired them to a spare motor and alligator clips to track (before I got a decoder tester)

[StewRRFan]

Winner, winner - chicken dinner.  Took the suggestions.  Had to make a set of test clips.  Doing this I was able to read the decoder.  So next question for help is - what do I do to make better electrical contact and what would go where?

[Steveruger45]

Winner, winner - chicken dinner.  Took the suggestions.  Had to make a set of test clips.  Doing this I was able to read the decoder.  So next question for help is - what do I do to make better electrical contact and what would go where?

Glad to hear the decoder is ok and issue is with the power pick up.  I’m not familiar with this loco but from the photo it appears the dummy board has to contact the long copper/bronze strips each side some how and I would suspect that is where the issue could be.  In that case you could solder on short jumper wires from the red and black wire attachment points on the board and solder the other ends direct to each respective strip.