# Aristo GP40 Problem



## bobvand (Jan 2, 2008)

Good morning, Could anyone give a little help on how to fix the GP40 so I can run double head trains with batteries. I know there is a jumper involved but my electronic skills are limited. I refer to the this site often for help ,could you please give some more details.Got to run more than one of these babies!!!!! 
Regards, 
Bob V.


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## blattan (Jan 4, 2008)

Aristo makes an MU cable, ART-29607. It may solve your problem. Since I have not used the MU cable myself, I don't know if it alone is all you will need. 

Bert


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## Guest (May 4, 2008)

bob, 
if you run a pair of jumper wires from frt battery plug to rear battery plug in the leed loco, this should solve the ploblem. what your doing is basicly bypassing the boards in the loco so power flows around the polly switch.. 
Nick...


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## bobvand (Jan 2, 2008)

Hi Nick ,What I did seems to have fixed my problem, I jumpered into the battery wires that come into one end of the locomotive.I then ran the two wires to the MU plugs at the other end, what I was doing wrong at first was then connecting the second wires back to the distribution board where they were from the factory. I think the way it is now is that I'm not pulling all that amperage through the unit to power the lead locomotive. It now only sees what it needs to run.Does this make any sense. I wish that the problem had been fixed before production of the GP40s. I only have one of the Dash 9s and it was just luck that it never ran right after my trail car when MUed .I have a couple of more GP40s to paint so I"all make the same fix, maybe I'll post some photos on the web and see if I did it right.


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## Guest (May 4, 2008)

You are correct Bob, all newer aristo locos can benfit by this modification, best to do them all that way you won't have to make witch ones were done and witch have not... 
Nick


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## Guest (May 4, 2008)

Pictures would be great, its been awhile since this subject has been talked about, and is good info for new guys and us old guys with bad memorys/DesktopModules/NTForums/themes/mls/emoticons/doze.gif 
Nick...


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## Greg Elmassian (Jan 3, 2008)

All you have to do is use a mu cable between the locos (from Aristo) using the existing connectors coming out from the locos. 

Put the track/battery switch in battery. 

There is a plug on the board inside to connect the batteries to, if I remember correctly, or else feed an unused MU cable "end". 

Now that's the way Aristo intended it. Unfortunately, they often put a resettable fuse inline with the MU "bus" inside the loco, and this fuse cannot handle the current for TWO locos. (doh!). 

The resettable fuse is about 3/8" square, thin, and orange in color. You have to move it so that it only protects the loco involved, not control the current for all locos. Wiring this will vary according to the loco model, and also the phase of the Chinese moon (Aristo products have random variations in wiring, especially wire color). 

You really have to check the wiring in YOUR locos to be sure. Pictures would help, but to be SAFE, you need to understand how your loco is wired, or have someone do it for you. 

Really. 

Regards, Greg


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