GG1 went batty

It does go batty... Menu/ Advanced/ reset engine/ feature reset/ That all I have without opening the thing up. Speaking of batty, can  you try a new battery I'm wondering if a completely dead or shorted battery  could cause this.   5 volt board... has the battery ever been changed?

Probably should have mentioned... its been feature and factory reset, deleted and readded, number changed, etc... 

Makes no difference.

If you can change the ID number and have it stick after a power down  it's not the battery .

Embedded video doesn't seem to work for me.  Are any of the coupler wires (PV wire) damaged and touching pilot frame?  G

No it doesnt look like it. They're still jacketed in the outer tubing and it looks complete. I just took the shell off, and it runs fine as just a chassis. Once you put the shell back on, it goes nuts. There's a lot of electronics in the shell, with the lights and pantograph mechanisms. I didnt see anything blatantly obvious that looked wrong in the shell either. 

G - I put it on Youtube so that you can see it.

With the engine in neutral and started up do the pantographs cycle correctly or does it short cycle like the video?

Select manual and see if you can run them up and down manually.  If one doesn't work right:

Unplug the pantograph motor plug (2 wire) for the one that won't cycle.  See if that solves the issue.

Otherwise unplug the 10 pin that goes to the pantographs, put shell back on and see if the solves the issue.  If so, I am thinking something along the pantograph operation causing the issue.

Anything that overloads the 5V power (smoke fan motors, pantograph motors) can cause the processor to shut down.

I have also seen coupler PV shorts near the coupler cause erratic stops because it also overloads the Power Supply board.  G

its stopping to take a breath!!

Sitting in place after startup, the pantographs work correctly and move through their complete range of motion. As long as it doesnt act up, they properly go up and down with change of direction. 

It was too late to mess with it too much last night. I played with it a bit this morning. With the couplers and shell connector (10 pin) unplugged, and the shell sitting on the chassis, it runs fine. Plugging the shell back in and it runs fine too, as soon as the couplers are connected, it goes crazy. If you blow the horn with the couplers connected, it'll kill it almost every time.... so your first guess might be right and its a coupler wire. I'm working from home today, but had to get working, so I didnt get a chance to take the couplers out yet and look at the wire insulation up close, but it looks a little tight on the coupler shank, so maybe thats whats doing it. Hopefully later I can take it apart and get the couplers out.

Smallest nick can cause it.  The vibration of motion or the horn can cause the erratic contact.

If you disconnect couplers, by the way you can do one at a time you might isolate the bad one,  Does the horn still trigger a shutdown?  If so a speaker going bad can short at full vibration and cause the same issue.   G

I took out the couplers last night and took a look at them.... one wire looked to have a very slight nick, so I unsoldered it from the coupler, wrapped the lead in heat shrink and soldered it back on. Wound up doing it for all 4 coupler wires while I had them out.... unfortunately, it didnt fix the issue. I then tried it with both couplers unplugged and the shell screwed down, and it still does it. I guess I need to check the pantographs, but they work and cycle properly when the engine is working... and they're not doing anything when the engine is running. I know everything is tied together in there. the purple wire nut is buried under the board, but I guess I need to try and pull it out of there and check that nothing came out. Its so annoying. It ran fine for a few laps after I fixed the couplers, then I stopped it, came back a bit later and it went back to acting up.  

I thought maybe the speaker, but its under the one of the boards. I guess I need to pull the thing apart and take a look... there's no distortion in the sounds though, so I have some doubts about that being the problem. 

I disconnected both couplers and the speaker... still does it. Plugged couplers and speakers back in, disconnected the pantographs one at a time, still does it. I guess its time to check the pickup wires through the frame. I've been trying to see sparks as its running, and I dont see any, but maybe its a real small cut. 

Die cast shell? Long shot,.... line the inside  of  the shell with electrical tape where you can  . especially above the main 5 volt board (if possible)

Pick up could do it too.  If the power cycles and is lost could cause the pants to do there reset.  I have seen loose screws on pickup terminals, broken wire under insulation at terminal, and don't forget dirty wheels causing loss of ground.  G

I'm following this one just to see what this turns out to be.

Well I give up. I cant find it. Not the pans, not the couplers, not the speaker, doesnt seem to be the pickups. There's continuity across them, the wire doesnt look damaged. I put a piece of heat shrink on one of the common wires because it looked a little rubbed, but that didnt fix it either. Short of releasing the entire wire loom and going wire by wire, I'm not sure where else to look. 

Now that I've wasted half the day trying to figure it out, I just threw it back on the shelf.

Any of you guys know if I can drop a 5V shell on a 3V chassis? I have another GG1 but its 3V, but if the shells swap, then maybe I can test the shell wiring on the other chassis and at least eliminate half of it.

I don't know if they wired that harness the same.  Might be risky.  Being a PS-2 5V it may be the board.

Check the solder joints were the 2 boards are joined via the connecting header.  Any signs of a cracked solder joint?  G 

Maybe unplug everything except the bare essentials &  start adding plugs...Start with battery plug,   center rail and chassis ground along with tack reader plug& motor leads plugged in  . Maybe you can narrow it down to one of the other plugs. 

 Forget this post, I went back and read were you said the engine runs fine with the shell off.  ??

http://mthtrains.com/sites/def...ction/20dl13801i.pdf

What about that two or more wires inside a shrink tubing "cable" , if used in GG1, might be rubbing together and taking unit apart/assembly moves them just enough to make problem dis/appear.

FWIW i  once saw where a loco wire insulation was spit a little longitudinally and could have caused a problem.  Wire was no where close to anything that caused split.  Vendors use as thin insulation as possible to conserve space and pennies,

One last question I promise.   any chance this is the problem? I'm not sure if the engine is new to you.

WARNING: The Automatic Operating Pantographs must be unlatched before power is

applied to the engine. See figure 2.

One of the things I do with the GG-1 is use a 10-pin feed-thru tether cable to connect the shell electronics to the chassis so I can test it on my rollers and have the pantographs connected and functional.  It also allows you to work on them and see them operate.

Gregg,

The Automatic Operating Pantographs must be unlatched before power is

applied to the engine.

Was that an MTH warning? I always understood, and it's been my experience, that the pantograph mechanism in MTH engines was much more forgiving of locked down pantographs.

There no danger at all with locked down pantographs, the mechanism just runs but it never even contacts the operating arms.  The spring loading is what moves them up, the motor brings them back down.

Yes it was in the link I listed , maybe it only applied to new engines right out of the box. anyway  it's not that.

I don't know why they have that warning in the manual.  I just worked on the pantographs of the MTH GG-1, and when they're latched, the lifting mechanism just runs back and forth with no load.  There's nothing I can see or imagine getting damaged having them latched and operating the engine or the pantographs.

John,

I expect that it's just a CYA on MTH's part.

Probably, from the design I can't see how it's a problem.  I'll have to look at the Lionel ones and see if they're different, they say the same thing in their manual.

John,

My understanding, second-hand, is that for the Lionel pantographs, the warning is one that is, indeed, correct.

I have the JLC GG-1, so the next time I have it out I'll take a look.  I've always unlatched them, but I haven't had to work on the pantographs yet, so I'm not really familiar with how they operate on the Lionel side.  I have to admit, the MTH scheme works very well and is simple and robust.

Same thing in conventional?  This engine should have a voltage reg mounted to the chassis someplace. Just wondering if it could be the problem . It has to be insulated from  the chassis. perhaps just   a loose screw or something touching it. Frustrating!!   

G or John, are all 5 volt board sets the same? I'm down to thinking its something on the board running for a bit before overloading. Once it overloads the first time, it just keeps doing it until shut down and left to sit. 

I have lots of other locos with working 5V boards, was thinking about swapping in a set of boards and testing it to see if thats the problem. This thing looks like a bear to replace boards in since it has the extra boards to run the pans and stuff.... if I can drop in a 5V set from another loco, it would be far easier to put a standard upgrade kit in a donor diesel.

Aside form the firmware on the board to operate the pans, you should be able to swap any other 5 volt board in and check basic features.

However, that's not something I would recommend until you're sure that some chassis wiring issue didn't take out the original board.

The board needs to be put on a PS2 test fixture to be checked out.

Unfortunately, as Barry states, the operating panto boards are a special Flash Board.

It can be converted to PS-2 3V or even PS-32 (though I am not sure the flash code for PS-32 is done yet).  THe 3V also needs to be a special order flash board.  I did one a few months ago after the 5V board died for a customer.

This issue that is weird is that you say it runs fine with shell off.  Unless that has changed. 

It could be those solder joints I mentioned.  Are you capable of inspecting and reflowing them.  You might have to take off the motor fet heat sinks to access the bottom.    G

Since everything runs with the shell off, I'd be chasing that first.  Hard to believe it's the board at this point, but anything's possible.