Need Advice PS2 Install Sunset Diesel

 I'm not going to guess on if they can handle it. I wouldn't know.

I would suggest causing the motor to (near) stall and seeing how high the current draw is, with the boards disconnected.

 I would install fuses inline, to protect the board.

You can upgrade the board for higher current motors, or use a special G gauge version. I have one on order for a year and a half now. I think they forgot me!

 I sent you an email.

Most motors used in O gauge trains measure 4-10 ohms. You should be fine. What MTH engine are you getting those readings from?

Pete

I would also bet that one motor on the board would be fine. I was taught that the current at stall is what to measure.

 MTH makes larger capacity boards for their big steamers with dual motors and higher draws. USA trains G scale engines are known for being big current draw engines and the HD version PS2 board can handle them.

As Stated, the motor resistance doesn't seem to be out of range.  I would make sure you don't have a motor lead grounding out to the chassis.  At start up the yel is + Voltage so if the white wire is touching chassis you complete the path.  Can be a pinch, nick in wire, or stray strands at the motor terminal touching can.

Joe, G is not really a HD board, they just heat sink the rectifier directly to the chassis and use a larger flash back diode also heat sunk to chassis for some models.  G

Thanks for the input guys.  The MTH motor was one loose in the parts bin, so don't know what engine it came out of.  Had a light lead come loose.  Is it possible that it went to ground and shorted out the board.  We are on a second board for this install and don't want to fry another.  LOL

GGG,

We've already swapped them with MTH for new boards, just trying to be sure to not toast another set.  Thanks for the advice.  Will check in if there are any more problems.

Thanks G!

CRH and Raymond Manley had taught me that a while back. I thought that made them stronger to handle dual motored G scale steamers. I came up with the HD name.

So the new board set is working and all's well?  Or is the behavior in the first post what you have now?

When the engine started moving by itself, did the lights and/or sounds come on too?

"...heat sink the rectifier directly to the chassis and use a larger flash back diode also heat sunk to chassis for some models."

How is this done and what is a flash back diode and what value does it have?

Double checked the resistance on several loose MTH motors and they all measure about 200 ohms.  To the electronics trained tech that is my BF this is too much for the boards to handle.

To me there has to be a way to do this...  right?

Charley,  If you look at the tech notes, they show the 1 gage boards.  Not needed for your application, I was addressing to Joe.

For your motors in stock spin the rotor a few turns than measure and slowly rotate, when the brushes have cleaned up and your on a commutator segment fully you should read between 4 and 12 ohms.  G