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My drawbar is causing a short

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  • Member since
    January, 2018
  • 6 posts
My drawbar is causing a short
Posted by Joey D on Wednesday, January 03, 2018 2:22 PM

Hello

I have a BLI P3 L1S. I notice that it would short the track. When I disconnected the drawbar from the tender there would be no short. When the drawbar would come in contact to the pin, thee would be a spark. What can I do to insulate the drawbar?

Thanks

Joe

  • Member since
    October, 2006
  • From: Western, MA
  • 7,802 posts
Posted by richg1998 on Wednesday, January 03, 2018 4:32 PM

Welcome.

Did you do any work on the loco or tender?

I remember some have a short with a Bachmann steamer when they plug both together. A tender truck swiveled 180 degrees.

Not knowing how the loco and tender are wired, the simple solution would be to make a plastic draw bar.

I lost a draw bar some years ago and made my own.

If you understand electrical, trouble shoot with an ohm meter.

Rich

N

  • Member since
    January, 2018
  • 6 posts
Posted by Joey D on Wednesday, January 03, 2018 4:58 PM

Rich

I did have to replace the decoder. BLI sent me a new one and I installed it. 

Joe

  • Member since
    February, 2005
  • From: Vancouver Island, BC
  • 21,432 posts
Posted by selector on Wednesday, January 03, 2018 5:33 PM

If it's a metal drawbar, you could put a kink into it so that it clears an axle better. I think this may be what is happening.  I had an early Paragon Niagara, and I believe my J1 2-10-4 had it as well, with a metal drawbar that caused all sorts of grief, including a short in one instance.  I removed it, carefully so as not to lose a screw, washer, or spring, and made two shallow bends so that the drawbar didn't touch whatever it was touching that was metal.  That worked.  Use needle-nose pliers, and go easy.  It may take you four or five goes at it before you get the right geometry.

Having good skills in track laying is important as well.  Abrupt changes in attitude along the axis of the tracks, such as sags or vertical kinks at joints, really can cause a lot of problems, and not just with drawbars or engine pilots.

  • Member since
    August, 2003
  • From: Collinwood, Ohio, USA
  • 6,389 posts
Posted by gmpullman on Wednesday, January 03, 2018 5:52 PM

Welcome   Joe!

 

I just checked the continuity of my L1 and found that the drawbar is attached to the frame of the locomotive which is "hot" with the LEFT rail.

The pin on the tender should not be electrically conductive at all. The frame is die-cast metal and it is possible you have a wire pinched between the shell and the frame.

I did not open the tender to see IF there was any electrical tie to the tender frame but, based on other Broadway engines I have, it should NOT be.

Broadway uses the outer two pins on the "pig tail" connector for rail power connections to the decoder in the tender.

As Rich mentioned, look for a tender truck• which may have been inadvertantly rotated 180° or if that doesn't cure the problem, look inside the tender for a pinched wire or short from the PC board to the tender frame.

• {edit} I took another look at the tender trucks and came to the conclusion that they are not easily rotated beyond normal range as there is a pick-up wire soldered to each one and the framework also prevents complete rotation, too.

Good Luck, Ed

 

  • Member since
    January, 2018
  • 6 posts
Posted by Joey D on Thursday, January 04, 2018 3:59 PM

Follow Up

I think I know the problem but not quite sure how to solve it. It seems I somehow magnitized the tender. Because I notice 2 tender screws (that I thought I lost) were stuck to the under belly of the tender. I removed them but still have the problem. I need to demagnitize the tender.

Joe

  • Member since
    August, 2003
  • From: Collinwood, Ohio, USA
  • 6,389 posts
Posted by gmpullman on Thursday, January 04, 2018 5:33 PM

Joey D
I need to demagnitize the tender.

I'm not sure that would really cure a short at the drawbar? I'm pretty sure the tender frame is Zamac or some kind of zinc alloy. What you might percieve as magnetized may be the speaker magnets.

Do you have an ohm meter or continuity checker?

Place the tender, with the harness plug still connected but the drawbar separated, on a short length of track.

Read between the pin on the tender and the left rail, then from the right rail to the pin. Meter should stay at 0Ω, or not beep if you are using the audio continuity checker.

Then try it again with the harness disconnected and see if you get the same results.

Since you already have two screws out (why did you take out the screws? Did you have the tender open already?) open it again and carefully look for a pinched or cut wire. Or a place where the PC board might be touching the frame.

My L1 had to go back to BLI, the only engine I ever had to return, as they had some decoder problems with some early runs. Mine would sputter down the track and die. They sent a new decoder but that didn't cure the problem. They sent a replacement engine and it has been fine.

Good Luck, Ed

  • Member since
    January, 2010
  • From: Chi-Town
  • 7,226 posts
Posted by zstripe on Thursday, January 04, 2018 5:57 PM

I agree with ED......Do as He suggested. If it somehow became magnetized, which I seriously doubt, (die-cast metal cannot be magnetized easily, you may have a slight magnetizing effect, but cannot be permanent) some wire must be touching the frame somewhere, or PC board shorted to frame.

Good Luck! Big Smile

Frank

  • Member since
    January, 2018
  • 6 posts
Posted by Joey D on Thursday, January 04, 2018 7:23 PM

I was able to solve the problem, but I really don't know why it happen. I insulated the 2 screws that connects the metal piece and decoder board to the tender. I used a plastic washer for both screws. Like I said earlier, I needed to replace the bad decoder with the new one from BLI. If anyone has these engines, the original decoder had a detached capacitor sodared to the bottom of the board. When I received the new decoder, I noticed that the new one was slightly different and called BLI. She said that the replacement and the seperate capacitor does not need to be sodared and to discard the capacitor. I don't know. but the plastic washers worked. Amen and thanks to all that responed.

Joe

  • Member since
    January, 2018
  • 6 posts
Posted by Joey D on Thursday, January 04, 2018 8:00 PM

Well that's not it either. It was the metal pin connecting the drawbar to the tender. I replaced it with another metal pin from unused BLI T-1 4-8-4. I'd still like to know why that pin became hot after replacing the decoder.

Joe 

  • Member since
    January, 2010
  • From: Chi-Town
  • 7,226 posts
Posted by zstripe on Friday, January 05, 2018 3:00 PM

Joey D

Well that's not it either. It was the metal pin connecting the drawbar to the tender. I replaced it with another metal pin from unused BLI T-1 4-8-4. I'd still like to know why that pin became hot after replacing the decoder.

Joe 

 

Glad You got it going..........But I would have to see that in My paws....why would one metal pin cause a short and another metal pin Not. Also why is the tender floor hot anyway? And it would have to be of a different polarity to cause a short.

Take Care! Big Smile

Frank

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