Help Kato F40PH problem - N Scale

[eja]

I recently got a Kato Amtrak F40PH and put a Digitrax decoder in it.  Soldered the tabs and checked everything out.

Once I put the shell back on it, it won't do anything, except immediately caused my NCE Powercab to restart.   Take the shell off and it works just fine !

Any ideas what I should be looking at ?


Thanks ....


Ed


 

[MK]

I'm going to assume you insulated that small section of the bus strip.  The other tricky part of this decoder install is the rear clip (fixed to the loco and not the removeable one).  You can't just drop the decoder in and solder the motor tabs.  You need to push the board back so the rear clip engages it and then solder the motor tabs.

Take a look at the blue square in this TCS picture.

[RBrodzinsky]

Check to make sure neither of the motor tabs can come into contact with the frame or brass strips once the shell is on.

[peteski]

If the Power Cab restarts that likely means there is a dead short in the loco.  I wonder if the pickup strips are misaligned somehow and are shorting through the metal chassis once the shell is installed?

[Mark5]

If the Power Cab restarts that likely means there is a dead short in the loco.

This

[tehachapifan]

Check to make sure neither of the motor tabs can come into contact with the frame or brass strips once the shell is on.

Agreed. As I recall, the motor contacts sit SUPER close to the truck pickup strips with no real barrier between them in at least one drop-in installation (not sure if it's the Digitrax one). Seems possible that whatever gap there is between one or both with the shell off is closing with the shell on...except this type of short is often fatal for a decoder, in my experience anyway. Maybe the Digitrax decoder has really good short protection for this kind of short?

In my Loksound (non-drop-in) install, I tediously wrapped some Kapton tape around the truck contact strips where the motor contacts come up. I know Peteski hates this method, and it's probably not the most bullet-proof way to go, but it seems to be working for the time being (although I suppose the tape could wear or tear on the contact strip edges over time). I also found the contact strips are hard to re-seat with too much Kapton tape wrapped around them, so I went with one wrap only....which I surmise makes the wear/tear issue more of a possibility. I haven't yet come up with a better barrier between these contacts. Has anyone else?

[eja]

OK,


I'll start buy checking the alignment  of the contact strips.....

.... but I can't see them when the shell is on !


 Sadly this is going to have to wait a while as we are about to do the over the river and through the woods to the grand-kids house we go thing.  At least I have an idea of where to start looking when we return. 

Thanks guys.

Happy Holidays to all.

Ed

[Ed Kapuscinski]

My F40 is a frequent pain. It's usually rock solid but every once in a while things get loose with that stupid "tab" and it's a B to fix.

[MK]

...I tediously wrapped some Kapton tape around the truck contact strips where the motor contacts come up. I know Peteski hates this method, and it's probably not the most bullet-proof way to go, but it seems to be working for the time being (although I suppose the tape could wear or tear on the contact strip edges over time). I also found the contact strips are hard to re-seat with too much Kapton tape wrapped around them, so I went with one wrap only....

This is what TCS says in their installation instructions to insulate the pickup contact strips.

[MK]

My F40 is a frequent pain. It's usually rock solid but every once in a while things get loose with that stupid "tab" and it's a B to fix.

Solder the motor tabs.

[Ed Kapuscinski]

Solder the motor tabs.

Oh I wish that were the only issue. It's that the hole that the stupid plug thing fits into is all chowdered up, so sometimes it all just comes loose.

[MK]

Just did an E8 for a club member and no soldering needed on the motor tabs.  My F7A/B done 10 years ago, still running fine, didn't need soldering.  But my Operation North Pole done last year required soldering from the get go.

Go figure!

[davefoxx]

I bought the 2017 Operation North Pole for my daughter, so I need to install the decoders in the F40PH and the cab car by Christmas Eve when Santa is supposed to deliver the train.  Looking forward to it (he said sarcastically).

[MK]

Dave,

Spend the extra $10 and get the TCS version of the decoder for this loco.  It has reversing marker lights for the loco when direction is changed for running cab forward.  Digitrax's version doesn't have this.  You need to do some minor board filing to narrow one end and modify two CVs.  Installation steps are the same as Digitrax.

http://tcsdcc.com/installation/n-scale/kato-f40ph-operation-north-pole/k5d7

From memory, TCS, added red LED(s) on the underside of the board to light the reverse marker light pipe(s).  The top has the headlight LEDs.

Most of my fleet is Digitrax but for this one, I got the TCS version.  Well worth it.

[davefoxx]

Dave,

Spend the extra $10 and get the TCS version of the decoder for this loco.  It has reversing marker lights for the loco when direction is changed for running cab forward.  Digitrax's version doesn't have this.  You need to do some minor board filing to narrow one end and modify two CVs.  Installation steps are the same as Digitrax.

http://tcsdcc.com/installation/n-scale/kato-f40ph-operation-north-pole/k5d7

From memory, TCS, added red LED(s) on the underside of the board to light the reverse marker light pipe(s).  The top has the headlight LEDs.

Most of my fleet is Digitrax but for this one, I got the TCS version.  Well worth it.

Thanks.  I already did, and it's standing by for installation.  I used the TCS decoder in my daughter's first F40PH, too, which is still working well to this day.

The decoder in the cab car, though?  Not so much.  That thing works on its own schedule.    Thankfully, my daughter doesn't know any better what the lights on the cab car are supposed to do in forward and reverse . . . until we put the new cab car on the tracks.    I may end up having to finagle that decoder's connections and replace it, if necessary.

DFF