# 370 GP7 not running



## mike costello (Aug 22, 2012)

I received a 370 diesel GP7 in the mail recently that appears to be almost new. However, it won't run at all. The e-unit cycles normally, but the motor doesn't budge as if its not getting any power. The motor is very clean and turns freely.
I've tried applying current directly to the motor with no success. Any ideas on how to test this unit? I don't want to tear into this 370 unless I really have to do so. Thanks for any replys. Mike.


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## flyernut (Oct 31, 2010)

At the minimum, you'll probably have to pull the shell to check for any loose/broken wires. At least that's where I would start.


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## mike costello (Aug 22, 2012)

flyernut said:


> At the minimum, you'll probably have to pull the shell to check for any loose/broken wires. At least that's where I would start.


I've already done all that. The wires are all ok. The commutator turns freely and the e-unit cycles as it should. It acts like no current is getting to the motor. Is there some way I can apply current directly to the motor and bypass the e-unit in order to test the motor? I suspect a bad commutator, although it looks just fine. As I said earlier, this GP7 diesel is almost like new and is extremely clean, so at first glance it should be running perfectly with routine servicing which I have already done. 

As a side note, I have collected and restored a lot of Flyer stuff and can usually solve most problems. I haven't done much work on diesels until now and this one is giving me a run for my money. Any advice is appreciated. Thanks, Mike


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## flyernut (Oct 31, 2010)

mike costello said:


> I've already done all that. The wires are all ok. The commutator turns freely and the e-unit cycles as it should. It acts like no current is getting to the motor. Is there some way I can apply current directly to the motor and bypass the e-unit in order to test the motor? I suspect a bad commutator, although it looks just fine. As I said earlier, this GP7 diesel is almost like new and is extremely clean, so at first glance it should be running perfectly with routine servicing which I have already done.
> 
> As a side note, I have collected and restored a lot of Flyer stuff and can usually solve most problems. I haven't done much work on diesels until now and this one is giving me a run for my money. Any advice is appreciated. Thanks, Mike


I only have 3 diesels myself Mike as I don't care too much for the motors in them.I'm not trying to insult your knowledge but there is power going to the tracks, correct. ( I really do apologize here Mike, but I always start with the basics.) Your springs and brushes are ok?? There's no binding anywhere? Wiring diagram is correct? Check for current going to the motor with a test light. I use test lights as I don't have any type of meters, and quite frankly, never used one, and don't know how. That's one of my many short-comings,lol..It sounds like a broken wire, wrong wiring, or maybe a bad e-unit.. I really don't know as these things are bullet proof. I'll be on the computer most of the day so keep me posted. Maybe I can throw something out there to help you... Loren


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## flyernut (Oct 31, 2010)

Do you have the correct wiring diagram for this loco?? How about the lock-out on the e-unit?


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## AFnewbie (Nov 26, 2012)

If you don't already have, here are some instruction excerpts.


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## mike costello (Aug 22, 2012)

AFnewbie said:


> If you don't already have, here are some instruction excerpts.


Yep, got the same repair manual and have read and reread it many times. Testing this design of engine is sure difficult vs steamers. Testing procedures for diesels is hard to come by. Lol.


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## mike costello (Aug 22, 2012)

I've compared everything on this engine (370) to a known working model I have which is a 372. Everything is pretty much identical wiring wise and both look good. Very frustrating indeed!


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## Nuttin But Flyer (Dec 19, 2011)

Again, not to insult your intelligence, are the fingers making good contact with the drum in the reverse unit? To check, use a toothpick or Q-tip to push each one against the drum with power applied.


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## flyernut (Oct 31, 2010)

Nuttin But Flyer said:


> Again, not to insult your intelligence, are the fingers making good contact with the drum in the reverse unit? To check, use a toothpick or Q-tip to push each one against the drum with power applied.


Yeh, I missed that!! I've had my 360 apart, 2 motors, and both of my 355's apart, having to completely over haul the motor. When I bought the engine at a train show, the seller told me it just came out of the shop, working 100%. I burned out the motor within 2 feet of running.Is there power going to the motor FROM the e-unit?? I would trouble shoot each "section" or "part". For instance, power on the tracks, then power to the trucks, then power to the e-unit, then power to the motor. I believe you're going to find the problem is in the e-unit, if there is no power coming OUT of it. If there is power coming OUT of the e-unit, then the problem is in the brushes next, then maybe the armature.Gotta excuse me, this is the time of day where I start eating Vicodin, so my thinking process is a little off.


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## flyernut (Oct 31, 2010)

Nuttin But Flyer said:


> Again, not to insult your intelligence, are the fingers making good contact with the drum in the reverse unit? To check, use a toothpick or Q-tip to push each one against the drum with power applied.


That's one I should have seen coming Don.. Well, I've always said, the more eyes and brains we have looking at a problem, the better chances are it will be resolved. As I've said in my previous post, use a test light and check each portion of the power supply to the motor.. The problem is there some wheres.


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## Nuttin But Flyer (Dec 19, 2011)

Mike -- There is also another issue that should be checked. You need to be assured that the armature is "centered" within the field. You do this by 'trial and error method' adjusting the small set screws in and out on either side of the field until the field is centered around the armature. If it ran before, it's unlikely this is the problem. However, it is something more to check.


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## Nuttin But Flyer (Dec 19, 2011)

Vicodin.....you gotta step up to the Oxycontin like I have. No need to "eat" those....one is enough.


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## flyernut (Oct 31, 2010)

Nuttin But Flyer said:


> Vicodin.....you gotta step up to the Oxycontin like I have. No need to "eat" those....one is enough.


I have breathing issues with those Don... I stop!!!!... Together with Tramadol, I can manage my pain nicely, lol. Actually, if I take 2 Aleve at bedtime, I'm pretty good to go for at least 2 hours in the morning. And you're right on about adjusting those little screws. I forgot about them...I still think there's no power going to the brushes from the e-unit... We'll see.


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## AFnewbie (Nov 26, 2012)

I agree with the thorough power tests, either with a meter or test lamps. I also like simple continuity testing with no power. On my similar diesel, I found a bad solder on one of the truck posts. It was physically connected, but there was no continuity.


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## Nuttin But Flyer (Dec 19, 2011)

I hope Mike checks all other suggestions before going to the adjusting screws. It's not likely they are the cause, but can be a possibility later if nothing else resolves the issue.


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## ChopperCharles (Jan 3, 2012)

If the e-unit checks out, I would check the field coil before I check the brushes or armature. The wiring on the field coil is pretty delicate, and I've come across several now where the place the wires attach to the field look fine, but the actual tiny field wire broke, and was no longer soldered in place. This is because the feed wires move during operation, and the tiny wires in the field don't like to take much stress. I've come across two diesels like this now. A simple fix with a bit of wire and a soldering iron.

Charles.


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## flyernut (Oct 31, 2010)

ChopperCharles said:


> If the e-unit checks out, I would check the field coil before I check the brushes or armature. The wiring on the field coil is pretty delicate, and I've come across several now where the place the wires attach to the field look fine, but the actual tiny field wire broke, and was no longer soldered in place. This is because the feed wires move during operation, and the tiny wires in the field don't like to take much stress. I've come across two diesels like this now. A simple fix with a bit of wire and a soldering iron.
> 
> Charles.


Could be! That's why I suggested testing each "part" of the circuit to see where power was being lost.I've also seen this in one of my steamers, but luckily, I just removed a turn from the coil and threaded it back through that small hole.


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## daveh219 (Sep 16, 2012)

Mike...just got a 370 at a local train show and wondering if you ever diagnosed and/or fixed your problem?? Don't see a final post of "success". Just checking

Dave


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## mike costello (Aug 22, 2012)

daveh219 said:


> Mike...just got a 370 at a local train show and wondering if you ever diagnosed and/or fixed your problem?? Don't see a final post of "success". Just checking
> 
> Dave


 In answer to your question, I haven't gotten the 370 working yet. Because it was in its box and barely used (if at all), I suspect it was defective from the factory, and someone just put it on the closet shelf all these years. I've tested this 370 for continuity using my meters to no avail. Visual checks reveal nothing.

I have been busy these last few months, so my Flyer hobby has been idle for awhile. The 370 is back in its factory box waiting for me to get more time to continue with this issue. With winter coming on, I should have more "shop time" to work on my Flyer collection. I've got several other pieces up for restoration, which I find relaxing & enjoyable. Will keep everyone informed when I figure the 370 out. Mike.


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## Nuttin But Flyer (Dec 19, 2011)

Sounds a lot like me Mike. I have a ton of Flyer projects waiting for the winter months. Let us know when she is up and running. I need some good experience with diesels as my previous attempts have not been too successful.


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