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Subject: USA Trains Lights - need 18v!

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fildowns

"Raindom" (UK)

Brakeman
Posts:42

10/02/2008 6:39 AM
The lights in my USAt GP7 require 18v before they suddenly switch on. I can then reduce the voltage, the lights gadually going dimmer until they finally go out just below 4v. Has anyone got any idea why this would happen? I have to wind up to almost full speed to get the lights on, and then slow down to my cruising speed...

Greg Elmassian User is Offline

1st Class Member
Carlsbad (San Diego), CA

Engineer
Posts:1311

10/02/2008 8:33 AM
If you have not modified the loco, and you are running on DC, you have a faulty main board, there is an on-board regulator, if you measure the voltage at the bulbs, you will find about 5 to 5.5 volts. The regulator should start passing voltage at a much lower track voltage. All the GP7/9's I have found use two wires to each end, and the headlights (GOW), number boards (small screw in bulbs) and the classification lights (red/green dual leds with 3 wires). I think you will need a new main board. Regards, Greg

Be sure to visit my site, lots of technical tips and modifications, and you can search for topics and key words. Click here for Greg's web site

fildowns

"Raindom" (UK)

Brakeman
Posts:42

10/02/2008 9:04 AM
Thanks Greg! At the bulbs, the voltage is 3v, On my USAt F3 which appears to have the same bulbs, the voltage is 5v. Could it be the voltage regulater in the geep that's gone? This could be an easier fix if so?

noelw

1st Class Member
Rio Linda, Calif. 95673
Foreman

Foreman
Posts:209

10/02/2008 11:07 AM
Yes like most has said.. Get it the reg./ board fixed or replaced. I had one go bad in my SD40-2 and it blow all of the lamps out.. Had to replace them and the regulater. Its not a easy job to replace all of them.. While I had it apart I change out the head lamp to LED's and added a 10 ohm risistor. 1/4 watt. between them Now head light come on at 6 volts to the tracks. But my Aristo Power supply only put out 18.5 volts. to the TM's. here in the boonies.

Rio feather says...One leave train running here and take coffee break may find Koi fish checking out how deep an Engine can swim when swing bridge is left open. It happen to Big Feather Tweedledum. Photo Album

fildowns

"Raindom" (UK)

Brakeman
Posts:42

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