What are my options to replace a PS3 board and drive motor on a Railking Imperial 30-20316-1

Thanks Alan, but alas.....

I thought I had fixed the truck (or whatever it was) and it ran several feet with no sparking.  When it started again, my curiosity to observe it made me run "one more foot" and that was it.   I have checked every ohm test I can think of to see if there is a short in the motor but it seems ok.  I should have taken a picture but I did find what appears to be arc evidence on the metal lip of the motor mount that connects to the truck.  If this is true, it was arcing between the frame of the loco and the motor mount. I thought I was seeing a pinched wire but not the case it seems. This is where the arrow points in my first picture.  I wonder what could be the deal with that? 

Well, before you put a PS/3 board into that one, you need to properly fix any issue with the motor grounding.  I suspect that maybe there's an internal flaw in the motor and one lead is internally getting connected to frame ground.

If you resolve the issues with the trucks/motors, I have PS/3 diesel boards.

@gunrunnerjohn posted:

Well, before you put a PS/3 board into that one, you need to properly fix any issue with the motor grounding.  I suspect that maybe there's an internal flaw in the motor and one lead is internally getting connected to frame ground.

If you resolve the issues with the trucks/motors, I have PS/3 diesel boards.

Good point.

From all I observed, this must be the case.  Strange, when I pulled the motor out and totally disconnected it, I did not see a short between the leads and the motor frame. Now that it is reinstalled in the loco and connected, there appears to be a  short between one of the motor leads and the external frame. No idea how that is possible but "it is what it is."

How easy are those motors to find?  the MTH mechanical parts view for this loco is not loaded on the web site yet.

I'd contact MTH Parts about the motor, they might just not have them loaded.

If the motor lead does not have a ground to chassis not sure that is the issue.  You can see sparking under truck from coupler issue, PV wire pinch, dirty wheels causing AC power sparking, Light wire 5V pinch.  So really hard to tell.  Did you pull motor and examine?  Board can be checked out separately.  Going to TMCC will loose most features and be more expensive than replacement board when back in stock. G

I got him covered for a diesel PS/3 board George, but first he needs to track down what's arcing.  Once he does that, he might find the board isn't dead after all.

@GGG posted:

If the motor lead does not have a ground to chassis not sure that is the issue.  You can see sparking under truck from coupler issue, PV wire pinch, dirty wheels causing AC power sparking, Light wire 5V pinch.  So really hard to tell.  Did you pull motor and examine?  Board can be checked out separately.  Going to TMCC will loose most features and be more expensive than replacement board when back in stock. G

GGG, I have pulled the motor and checked it and will do the same when the new one arrives, comparing various ohm readings.   The photos below seem to show where I think arcing is occurring.

Did you closely examine the wires running under the gray plastic interior piece.  Can't tell you how many times inspecting an engine for a blown board that everything looked fine until I looked under the interior piece to find the hidden section of wiring pinched or damaged.  Saved me smoking a new board. Sometimes that arcing occurs from the ground side.  The truck wheels pickup ground AC and transfer it to truck.  With shorted wire you're seeing the AC ground sparking between chassis frame where the pinched wire is, and the truck connection to the chassis that has the AC ground power.  Even if not pinched, insulation can be split.  G

@GGG posted:

Did you closely examine the wires running under the gray plastic interior piece.  Can't tell you how many times inspecting an engine for a blown board that everything looked fine until I looked under the interior piece to find the hidden section of wiring pinched or damaged.  Saved me smoking a new board. Sometimes that arcing occurs from the ground side.  The truck wheels pickup ground AC and transfer it to truck.  With shorted wire you're seeing the AC ground sparking between chassis frame where the pinched wire is, and the truck connection to the chassis that has the AC ground power.  Even if not pinched, insulation can be split.  G

Thanks, your guidance and suggestions are pretty close to what I did to start into this. Initially I thought I found a pinched wire under the grey interior piece as you note.  Rerouted that, put electrical tape on the wire and put the loco back on the track.  It ran ok for a few feet and started again sparking.  that is when I shut down and decided to re start to go another foot to look more closely. My curiosity was rewarded with the extra smoke, we all hate.  I will certainly do this inspection check again when I go over the checkout details for the new motor installation. 

The new motor showed up from MTH yesterday and I was able to spend some time tonight looking it over and comparing with the original.  Dimensionally, I bought the correct one.  On electrical characteristics, the old motor showed "OL" when tested from either winding connection to every piece of external metal I could imagine.  So, no obvious short to ground.  The big difference between the old and new involves the simple test of the resistance between the two motor leads.  The new motor was typically 2-3 times the ohms of the old as I rotated the shaft and checked resistance.

Not knowing how the inside of the motor is built, is this convincing evidence that something is shorted in the old motor, and it is the culprit?  Time to install a new PS3 board?

Typical resistance of the old motor

Largest reading on the new motor- nothing close to this on the old motor.

I thought I would cap this story of woe and destruction with some concluding details.  GRJ was nice enough to send me a PS2/3 board and I did what I thought was due diligence to find the short by replacing the front drive motor.  After inspecting wires in the vicinity of the front drive, trucks, etc.  I installed the board and fully expected success.

Not so fast unfortunately.  Not to go into details but no joy in mudville- something was still shorted.  I happened to be in GGG's neighborhood in the past few days and he was nice enough to take a look to see if he could do anything to diagnose the boards or see an obvious issue.  He replaced a few board components but there were deeper problems, and we all know current part availability issues. He thought a likely suspect based on what he observed in the damaged board was the smoke unit.

When I got home, I did a complete disassembly of the wire bundles and found several wires to the smoke unit that had been obviously damaged in manufacturing (as GGG predicted).  If you look closely at the arrow, you will see several extremely bare wires.

Live and learn on finding shorts- I have no idea why sparks were showing at the front truck if these shorted wires were the cause. Perhaps I had two issues- 1) bad motor as originally diagnosed (showing the original sparking). 2) hiding in the weeds were these stripped wires. During board installation, I jostled these damaged wires to the smoke unit and put them into play. 

Who knows?  At this point I will probably part this loco out.

That's ugly, it's a shame you sacrificed a brand new PS32 board on that! 

This was a PS-3 Diesel, not PS-32.  When you have the arc and spark around truck and motor you typically are dealing with either a poor AC connection and the AC is arcing via chassis ground, or you have PV short which ultimately comes from the main bridge rectifier so it can arc to AC common.  So motor leads, coupler leads, heat element all sources that use PV on a PS-2 or 3 board.

I did state motor or smoke as possible because his board had a power supply chip failure and both motor fets shorted.  With no PS-3 boards available I did not exert too much time to find cause once I knew both boards he had were dead.  G

This era locomotive had issues with too much coating on the wheels which caused arcing from the frame to the truck.  Clean the black off of the wheels.  I've seen quite a few of these with this problem.

@David Minarik posted:

This era locomotive had issues with too much coating on the wheels which caused arcing from the frame to the truck.  Clean the black off of the wheels.  I've seen quite a few of these with this problem.

Dave - please, expound upon this statement. Thanks.

@Mark V. Spadaro posted:

Dave - please, expound upon this statement. Thanks.

Mark,

It produces the same scenario as a loose wire or any poor connection.  Arcing will occur and heat will be generated.  We all tend to gravitate towards a power wire being shorted when we see sparks but the same can happen with a poor ground.   Think of a loose ground on a car battery or trying to establish an arc on a welder that you forgot to hook up the grounding cable.  It will look for a solid ground!

Clean the black off of the wheels.  It is an easy thing to try and if it doesn't work....... well at least you have clean wheels.

I'm with Dave on this issue.  I have an MTH PS/2 A-5 with the 3/2 Rail switch, it has issues running for the same reason.  I mean to disassemble it and clean off where the wipers hit the inside of the wheels as well as the black on the wheels themselves.  It's on the to-do list.   While it's apart, the 3/2 Rail switch will be history as well, why they used a ten cent switch to carry track power in these is a total mystery to me.

@hokie71 posted:

I thought I would cap this story of woe and destruction with some concluding details.  GRJ was nice enough to send me a PS2/3 board and I did what I thought was due diligence to find the short by replacing the front drive motor.  After inspecting wires in the vicinity of the front drive, trucks, etc.  I installed the board and fully expected success.

Not so fast unfortunately.  Not to go into details but no joy in mudville- something was still shorted.  I happened to be in GGG's neighborhood in the past few days and he was nice enough to take a look to see if he could do anything to diagnose the boards or see an obvious issue.  He replaced a few board components but there were deeper problems, and we all know current part availability issues. He thought a likely suspect based on what he observed in the damaged board was the smoke unit.

When I got home, I did a complete disassembly of the wire bundles and found several wires to the smoke unit that had been obviously damaged in manufacturing (as GGG predicted).  If you look closely at the arrow, you will see several extremely bare wires.

Live and learn on finding shorts- I have no idea why sparks were showing at the front truck if these shorted wires were the cause. Perhaps I had two issues- 1) bad motor as originally diagnosed (showing the original sparking). 2) hiding in the weeds were these stripped wires. During board installation, I jostled these damaged wires to the smoke unit and put them into play.

Who knows?  At this point I will probably part this loco out.

That's not a damaged wire from manufacturing per say. That appears melted, probably caused by a short. Blue wire looks like it melted and damaged the surrounding wires. That blue wire is probably PV to the smoke resistor. Check to see if the resistor in the smoke unit had continuity to the case of the smoke unit. If it does that's what took out both boards, a smoke resistor short to ground.