E unit has me stumped need advice

1269 views
14 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    December 2006
  • 105 posts
E unit has me stumped need advice
Posted by northernpike on Sunday, January 13, 2019 8:50 PM

Need some advice.  Picked up a beat up 2328 Burlington GP7 at antique mall.  Outside shell was a mess.  Inside is clean.  Horn even works.  Figured chassis would be good for my wabash shell.

I changed the brushes, cleaned commutator, lubed, etc.  inspected e unit.  Fingers look new, drum looks new.  Appears to be a rebuilt unit, exceptionally clean.  It runs strong once in a while.  The lights then flicker and go out but it keeps going in one direction.  When in neutral, plunger cycles, unit buzzes, etc but nothing.  If you tap e unit it will catch and take off but only  one direction.  Moving the lever does nothing.  Fingers all making contact with drum, nothin bent. I took out plunger and tapped it with hammer to demagnetize.  Solder joints solid.  Rebuilt many e units but never seen this.  What’s going on?  

I appreciate any advice.  Short of replacing e unit, at a loss.

thanks 

Tom

  • Member since
    December 2006
  • 105 posts
Posted by northernpike on Monday, January 14, 2019 10:21 AM

Update

Tore e unit down again.  Cleaned all fingers,drum, checked for notches in drum.  All good.  Reassembed.  Grounded frame, energized.  Cyles like new for 15 to 20 times, then pawl just freezes in up position.  If I pull it back down with needle nose it’s ok for a bit then freezes up in up position.  What’s going on?  Can the pawl get magnetized?  Checked for burrs and cleaned the pawl shaft.  Stumped.  Help!!

KRM
  • Member since
    January 2011
  • From: North Bluff above Marseilles IL
  • 5,724 posts
Posted by KRM on Monday, January 14, 2019 12:14 PM

Wish I could help but it sounds like you have done everything I would of tried???? Would like to know what you do find, if you find anything.

Joined 1-21-2011    TCA 13-68614

Kev, From The North Bluff Above Marseilles IL. Whistling

 

  • Member since
    December 2006
  • 105 posts
Posted by northernpike on Monday, January 14, 2019 12:42 PM

I think I finally found the answer.  It’s missing the grounding c shaped washer between the motor and frame.  Once I order and install one will post results.  

thanks

tom

  • Member since
    April 2005
  • From: South Carolina
  • 9,568 posts
Posted by rtraincollector on Monday, January 14, 2019 3:32 PM

I've seen the missing motor spring cause problems before, so you might be on to something. I have about 8 GP's so I keep one in stock normally, as I have gotten many does not run or untested ( so you know something is wrong lol) with out them.

Life's hard, even harder if your stupid  John Wayne

http://rtssite.shutterfly.com/

  • Member since
    October 2011
  • 887 posts
Posted by TrainLarry on Monday, January 14, 2019 5:31 PM

I've had that exact problem a few times before. Drove me nuts trying to figure it out. The fix is to replace the drum. The cogs of the drum wear just enough to cause the pawl to hang up.

 

Larry

  • Member since
    December 2006
  • 105 posts
Posted by northernpike on Friday, January 18, 2019 5:19 PM

 New motor truck ground spring arrived for my 2339.  Put it in, same thing.  I replaced the drum with one from my parts box.  No grooves, looked new.  Now it goes a foot or two in forward then stops, skips neutral and jumps in reverse, almost like a gang car.  Sometimes the lights are on sometimes not in forward.  Sometimes e unit just chatters.   Fingers are all good no pitting, bends, etc.  Sometimes it just sits without lights or buzz until I bump it.

I took the shell off my other gp7, 2338 to see if I crossed something on the wiring, etc..  2338 always runs great.  I did notice it was also missing ground spring so I know it’s not motor truck ground spring causing issues in 2339.

Dont  know what else to do on 2339  Need advice, please.  Should I replace the e unit entirely? I went over my Greenbergs repair guide, see nothing missing.  Stumped.  Help, please!

thanks

Tom

  • Member since
    January 2009
  • 1,813 posts
Posted by 8ntruck on Friday, January 18, 2019 10:06 PM

The e-unit jumping from forward to reverse suggests that you might have intermittent power to the e-unit.  Is there something shorting out between the center rail pick up rollers and the e-unit?

I've got a early 50's Hudson that acted like it had an erratic e-unit.  Turns out that the pick up wire to the whistle relay in the tender was shorting out on the frame of the tender.  Didn't figure that one out until I happened to see sparks under the tender one day when it switched directions.

Good luck.

  • Member since
    November 2011
  • 1,317 posts
Posted by Postwar Paul on Friday, January 18, 2019 10:08 PM

Hi Tom,

I suspect you have an intermittent open some where in the circuit. The light should stay on steady, unless the bulb is loose in the socket, so should be a good indicator. You may also have more than one problem.

You can try to bypass the E unit to make sure the motor runs fine, but the light going out is suspicious...

I have a 726 rr that had problems with the ground side of the circuit initially...

Paul

  • Member since
    November 2011
  • 1,317 posts
Posted by Postwar Paul on Friday, January 18, 2019 11:28 PM

I've got a little trick for you :

 you mentioned tapping on the engine, and it will run.

So , take off the shell, and dim the lights. If you can tap the engine, and it starts, you might just be lucky enough to see a spark somewhere. This is the weak spot, or bad connection.

 Consider that these old trains have everything grounded to the frame, and then through the frame and wheels to the outside rails. All it takes is a little rusty or dirty spot to  interrupt that ground path.

Paul

  • Member since
    December 2006
  • 105 posts
Posted by northernpike on Saturday, January 19, 2019 12:50 AM

Hi Paul

Tried it.  No spark.

i isolated e unit.  Cycles perfect.  Motor fine.  Bulbs bright.

Engine runs for a second when cool.  Then stops.  No lights, nothing.

When cool again, same cycle.  When I touch positive to e unit where all wires land and other to ground all is good.  It seems to be between e unit and pickup.  The pickup is wired with super flex stranded, #22 wire.

Could this be problem?  I polished all rollers and wheels shiny bright.

The base was repainted.  Could the paint be interfering with the ground?

  Should the paint be scraped off where the collector truck touches frame?

Thanks for all the insight.  Will get it eventually.

thanks

tom

 

  • Member since
    October 2011
  • 887 posts
Posted by TrainLarry on Saturday, January 19, 2019 9:30 AM

You seem to have stumbled on the answer. You need to scrape the paint off the frame where the trucks are attached. The frame gets its ground source through the trucks.

 

Larry

  • Member since
    January 2009
  • 1,813 posts
Posted by 8ntruck on Saturday, January 19, 2019 1:23 PM

You might also check the solder joints on the superflex wire.  It is possible that enough strands have suffered fatigue failures at the solder joints that the wire looks connected, but is really about ready to fall off.

Scraping the paint off of the frame might also help.  I'm thinking that the original frame finish was a black oxide treatment akin to gun bluing.  That would leave a conductive surface, where paint would be something of an insulator.

Again, good luck.

  • Member since
    December 2006
  • 105 posts
Posted by northernpike on Saturday, January 19, 2019 1:30 PM

Success!  It was the collector roller arm spring.  The tip of one of was bent very slightly touching the arm and shorting it out.  The only clue was the rollers were really hot.  I also installed a solid piece of wire for the pickup, ditching the super flex.  Bent the spring out of way and wrapped with electrical tape.  Runs great.  Thanks to the group for all the advice.  I learned a lot about geeps!

Tom

  • Member since
    November 2011
  • 1,317 posts
Posted by Postwar Paul on Saturday, January 19, 2019 5:29 PM

Very nice ! Glad it worked out !

Join our Community!

Our community is FREE to join. To participate you must either login or register for an account.

Search the Community

FREE EMAIL NEWSLETTER

Get the Classic Toy Trains newsletter delivered to your inbox twice a month