Kato M250 Rough Running

[Kotori]

Just recently got a Kato M250.  It was brand-new, and when I run it, it has constant jerking motion and headlight flicker.  At certain points on the layout it will just freeze and not move at all.  All connections of unitrack seem to be secure.  Neither my N700S or E3 do this.  Anyone know what might be wrong?

[bill937ca]

Have you cleaned the track recently?

 

[Kotori]

@bill937ca Just after making this post, and the power car’s wheels too.  Still runs rough, but it’s improved a little.  Still occasional flicker and jerking motion; it seems to not like turnouts.

Edited February 5 by Kotori

[katoftw]

Be more likely the running gear like bogies have taken a jamming hit in the shipping process.

 

I'd lightly pull out the bogies and see if you hear a click. A wiggle would hurt also.

[Kotori]

@katoftw Gotcha.  I’ll see what I can do; hope DHL didn’t jam my model in shipping but oh well.  Any idea where I can find a disassembly guide?

[katoftw]

The cleaning section of the instruction sheet that comes with the model, normally has the ways to remove the bogies.

[inobu]

Check the wheel pick ups above the trucks. Lights going out is lost power to the light board.....

If other trains are good then its the 250.....

 

Inobu

[Kamome]

If it's brand new, possibly

1. something is binding
2. something isn't seated correctly.
3. A loose electrical connection or shorting on split chassis (motor contacts, lightboard)

Disassembly

This blog has images of the loco disassembled for DCC fitting. It may help at least knowing which parts come away from each other.

 

https://vivant.jp/M250-seisakuki-DCC.htm

 

Once you have taken it apart, may be a good point to test the motor with the controller you use on your layout. Does it run smooth or still rough? 

 

Out of Position Bogie, Shaft or Gear Binding

Essentially the truck parts and chassis clip together and can get thrown about during transit, even domestic shipping. The main culprits are often the drive shafts or the truck assembly. It may be as simple as checking to see if anything is out of line. Before you go ahead and disassemble, does the loco sit straight on the track? Sounds dumb but it might indicate which end is the trouble. There are very fine tolerances in N scale and something misaligned can sometimes be obvious when you look closely.

 

The trucks/bogies unclip from the chassis with the drive shaft attached. The hex on the end of the driveshaft fits loosely into the fly wheels on the motor in most cases, but clips into the drive-cup of each bogie. Once you have removed them, check the condition of the drive shaft. It shouldn't have any stress marks and should be straight.

 

Taking apart the truck/bogie If you look in the third image down on the above blog page, the small black clips behind the brass pick ups on the truck, these allow you to take the assembly apart, just push inwards and down on the 2 together. The main body of the truck is in 2 parts. Be careful not to lose or bend anything. The wheels will push down and out with the contacts as the base is removed, be especially careful to keep all of the parts for the worm gear as these are fitted in loose.

 

Take photos as you go will help greatly on your first maintenance outing but Kato products are all similar in design. Clean if necessary and put back together. Test the trucks before adding worm gear back in. They should roll back and forth freely without too much downward pressure from your finger. If they roll ok, add the worm gear and drive shaft back in. Carefully slide the drive shaft back up into the motor flywheel and clip the bogie back to the chassis.

 

Electrical Continuity or Shorting.

Something not seated correctly may cause an issue here too. The power needs to go through the 4 wheels on one side of the loco, up the bogie pick ups, along the brass contact strip, through one side of the weight, into the motor pick up. Then the same in reverse on the other side.

If anything is not in correct position, it will cause continuity issues. Also if there is anything bridging the circuit between the 2 metal sides of the chassis, that will cause a short. The plastic mount around the motor keeps the 2 pieces apart. May also be good to ensure the lightboard is correctly installed. Check to make sure that everything is in correct position and work backwards to rebuild. 

 

[Kotori]

@Kamome Thanks for the write up! This is super helpful, and I’ll be definitely checking each thing.