# usa engine trouble



## cj and m (Feb 6, 2010)

Hello , My name is Mike Dorsch and this is my first post on this forum.I have a usa gp30 that will not pick up from the engineer front wheels or slider. the other 3 corners of the engine work fine . I swapped out the motor block with another engine and it still didn't work. I have the body shell off and using a voltmeter I tested from the main circut board and found that the rear pick ups were fine and the red wire on the other pick up was good also. The front black was dead . I tried jumping with a wire past the conector , going directly to the board and still no luck . I even re soldered the 2 wires and still nothing. I can't think of anything else to try . Anyone ever had this problem before ? Can someone tell me how the 4 wires coming off the motor block are used ?


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## Greg Elmassian (Jan 3, 2008)

There are 2 ways the loco picks up power... there is a wire to the "bearing" at the end of each axle, the wire runs from that. 

There are also internal wipers inside the motor block. 

The axle end is a bit of a loose fit, so testing continuity without the loco putting weight on the wheels (and thus the bearings and axle tips) might not show connectivity all the time. 

If you have checked that all 4 wires to all 4 axle tips work, then look inside the motor block. 

WARNING! It is extremely easy to put the motor blocks back together wrong! The 2 axle motor blocks are different from the 3 axle ones. Read my site under usat locos. Note the position of the "bushings" in the motor block when you take the "lid" off. Follow my tip to hold up the motor block from underneath when reassembling. Do it wrong and you trash the gears. Guaranteed. 

It's not hard to do, but if you don't follow the procedure to ensure the axle does not shift when reassembling, you will damage the gears. 

You have been forwarned. 

Regards, Greg


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## cj and m (Feb 6, 2010)

Thanks for the reply Greg . I replaced the original motor block with one that I knew functioned correctly and still the engine would not pick up from the one side . The problem has to be somewhere between the motor block and wherever . A little history of this engine . I bought it new a few years back and it ran great , then all of a sudden for some reason this problem developed . I'm wondering if the connector is bad or maybe the main circut board. I'm about ready to pull the gears out of it and make it a "dummy" unit !


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## John J (Dec 29, 2007)

Welcome to MLS Mike. If you changed the motor blocks and the problem is still there then I would think it is in the boards it self. If there are only 4 wires coming from the motor block.....Two have to be motor Wires Two Contact wires.

I would do a continuity check with your meter Two wires will show some kind of resistance the other two nothing. Does this have sliders? YOu should get continuity from the sliders to one of the wires coming from the block 

But as I said before I do not think you have a motor block problem. 

What about switched the motor blocks end to end. Does the Problem follow the block?


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## cj and m (Feb 6, 2010)

Hi John, Its not the motor block . I switched them end to end and even tried one from another unit and still no pick up from the left front. I'm getting juice to the board. If I put the connection to the front truck it shows voltage and likewise when I put it to the rear truck it shows voltage. When I criss cross the wires from the good pick ups I get voltage, but when I do it from the bad corner I don't. Crazey hugh . I'll try a new one from Charlie Roe. I'll keep my fingers crossed.


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## Dan Pierce (Jan 2, 2008)

Sometimes you get a bad crimp on a wire where there is insulation in the crimp preventing solid contact with the wire. 

The motor blocks are OK as you swapped front and rear and the problem stayed with the engine, not the motor block. 

Perhaps there is a bad solder joint on the circuit board or a broken/burnt etch? 

You should be able to meter out the wires from one block to the other and find the ""open"" and repair it. 

If you had the engine on a piece of track when measuring voltage, you could have been mislead. 

Place the engine on a work bench and just measure the ohms on the side not working to find root cause.


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## cj and m (Feb 6, 2010)

Thanks for all the advice ! I have to admit my electronic ability is very limited.


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## tomplatten (Sep 12, 2008)

I had a USA NW-2 with the same problem on the front truck! I finally gave up and sold it!


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## Santafe 2343 (Jan 2, 2008)

*I have had two go bad on me, the same way, a GP-38 and a GP-9 then I repaired 4 others for friends. It always turned out to be the circuit board burnt. The worst one he had was his NW-2 Switcher, we took all the circuit boards out of that one and made it strickly battery operated. I just got rid of all mine. *


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## aceinspp (Jan 2, 2008)

I would check when opening the motor brick and make sure all wires there are making contact. I've had a similar problem but was able to correct by checking all connections. Later RJD


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## cj and m (Feb 6, 2010)

Thanks guys for all the responses ! This is a GREAT website ! I decided to put it all back thgether and run it as is for now , making sure the wheels and sliders are clean totally . I ran it like that last year . This was one of my winter projects . Maybe someday i'll get another circut board and see what happens . Have fun !


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## Johnn (Jan 5, 2010)

I have 2 GP-38s with over a 100 in service hours on them with no issues. they really do run flawless, Thanks USA trains for making top notch stuff.
Johnn


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## cj and m (Feb 6, 2010)

I called Charles Roe today and they told me it was the circut board . He said that it derailed at one point and the trucks shorted across the rails causing the board to burn out . It sounded as if they have dealt with this issue before . A new board is $35.00 plus shipping . Your right , I have had great performance from my USA equiptment as well . This was my first problem with any of their products .


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