MTH 2 rail Allegheny DCS question... help!?!??!

I’m not a pro or expert by any meaning of the word, but since its related to movement, I would check for binding in the drive train.  Maybe something got arc welded when it derailed?

Barring that, it sounds like maybe the output drivers on the motor controller part of the board may have cooked themselves.

Hopefully others will have some more ideas for you if it’s not the drive train binding.

Thanks for the feedback.  I've looked over it and over it.. no binding anywhere.  Everything turns smoothly.  I'm wondering (and worried) about your second idea about some part of the board that controls the motor got cooked somehow... I wish there was an easier way than testing a new board.  Thanks for your input!

Do you have fuse or breaaker protection on your power source  to the rails?

Check to see if you got something caught in the mechanism like a metal sliver or of you have a bent wiper. Sometimes, those items are situated such that when the unit moves it shorts. Had something like that happen with one of my diesels.

@AGHRMatt posted:

Check to see if you got something caught in the mechanism like a metal sliver or of you have a bent wiper. Sometimes, those items are situated such that when the unit moves it shorts. Had something like that happen with one of my diesels.

I’d agree with you on this one Matt,….I’d be looking for something stupid or silly happening before I went cussing’ the electronics…..

Pat

Just a thought, unplug the motor and then test it with a DC supply.  If the motor or drive train has a problem, that could cause what you're seeing.  You mentioned testing the motor, just don't know if you ran the motor and drivetrain on your bench test.

Sadly, I'm in the cooked electronics side of the camp, but I could be wrong.  It sounds like when you crack the throttle the board is ramping up the motor drive and something is shorted and causing the issue.

Sounds like a motor fet short.  It is repairable usually.  G

Thanks to all- when I bench test the loco I can run the motor while it’s connected to the drive train.  Everything works perfectly. I will continue to look for something else- but I’m guessing something happened to short out the board.  It’s bizarre though…. Every single function works perfectly on the dcs board….

and yes, I do have a fuse between the dcs tiu and the track… boy I sure love electronics!  Make it all just DC again!

Side note and question…  I know most 2 rail O scale guys go the DCC route… I chose to stay with DCS due to it’s simplicity.  It’s easy to use and I love the speed matching and building a consist is easy.   Are there other 2 railers that enjoy using DCS over DCC?

thanks again!

What is a motor fet?

It's the electronic part that switches power to the motor.  I agree with George, that's my top suspect with your symptoms.

@Rick Stoffregen posted:

Are there other 2 railers that enjoy using DCS over DCC?

Me

Where would that be located and how could I test it to find out?

Hahahaha!  I was going to say other than John sethian and myself!  Hope you’re doing well John!

That's on the PS32 board that was part of the upgrade.  It's a surface mount component, on the bottom of the board.

One of the two circled components.  I didn't look them up to see which was the likely one.

Great work gunrunner!  I wonder if I could order a new fet?  I will take a look at that part to look for any discoloration or something indicative of a failed component?  

I appreciate all of the help this group offers… you guys are incredible resources….

Truthfully, I'd let George fix it unless you're experienced with surface mount repairs.  It's real easy to turn a relatively inexpensive repair into a new board if you screw it up.

@John Sethian posted:

Me

me 2

@Rick Stoffregen posted:

Great work gunrunner!  I wonder if I could order a new fet?  I will take a look at that part to look for any discoloration or something indicative of a failed component?  

I appreciate all of the help this group offers… you guys are incredible resources….

I’d second what John recommends,….George repairs all of my DCS boards,….he’s incredible with that stuff!…

Pat

Excellent! How can I get it to George?  I have not sent anything to him before…..

@Rick Stoffregen posted:

Excellent! How can I get it to George?  I have not sent anything to him before…..

Click on his profile …

Pat

GGG | O Gauge Railroading On Line Forum (ogaugerr.com)

Update…. I found the culprit!  After much trial and error, I found one of the brake shoes was bent and touching the wheels causing an intermittent short.  I swapped the DCS board out and it runs great!  Guessing it did fry the fet board for the motor driver, so GGG, I’m going to contact you to send it to you for repair if you can!

thanks all!

make sure the brass pins inside the shell don't touch the smoke unit. I had the mounting pin from the whistle touch the smoke unit's solder pads intermittently. It drove me nuts trying to find the trouble until it became obvious. It would only touch when the shell twisted like going around curves.

Bend them over fully and insulate.

Thanks for the advice!  I had not thought of that but I may do that before I put the shell back on her today.  I feel confident that it was the brake hanger and shoe, because I recall seeing a bit of "blue" sparking coming from that area in question.  Now I just need to send that board away to have the FET replaced. 

Thanks again Joe!

I model in 2 rail O Scale and also 3 rail O gauge.  I use DCS and can also run conventional.

Hello Hudson5432... I am assuming you are running DCS in 2 rail O?  I know most of the 2 rail purists insist on DCC, but I find it much harder to work with than DCS.  The other cool thing about DCS is the speed control.  I don't have to "speed match" in DCS as you do with DCC.  This is especially nice when I'm running trains for a crowd during the last Christmas party at our house.  I had about 5 consists running and I just set matching speeds and away they go and I don't really worry about collisions!  ( I do keep an eye on them and adjust speed if needed however!)

Have a great day!