LED lights don't work on GP 40

[badkarma]

Hi, I'm converting all my Bachmann trains from DC to DCC.  I converted 2 already. A F7 and GP50 and all went well. No problems with the LED lights and decoder installation. The 3rd one, a GP40, works find, but no lights. Front or rear does not light up. Is there an easier way to test the lighs to see if it works or to test the board? I have a resistor already attached to one leg of the LED's. I know the difference about the polarity. Like i said everything worked on my other 2 trains.

[richg]

Get your multimeter out and check for 12 vdc at the decoder light terminals. Very easy. Anyone doing DCC at this level should have a multimeter.
A nine volt battery and 1k resistor is a good way to check an LED before installing.
An ohm meter cannot be used to check an LED.

Rich

[bapguy]

What brand of decoder? Is it a board style like the Tsunami AT1000? Some decoder boards have the resisters built in. So if you add another not enough power is getting to the LED. Hook up your volt meter to the out put for the lights to see what voltage it is. Make sure F0 is on. Joe

[richg]

Attach the voltmeter leads right to the two LED leads. If yours sees 12 volts, the LED is burnt out. With the LED lit, should be about three volts.
Even if there is a resistor on the decoder, you should see a dim LED and maybe a volt.
I have seen LED's on Bachmann steamers with as much as 2.6 k resistance show light. Kind of dim though.
One SoundTraxx board decoder I know of has LED resistors and I don't think it is for your loco.

Rich

[badkarma]

Thanks for all the information. I will check it out with my meter. The DCC board is a bachmann H601X PCB01 decoder.

[richg]

Did not expect that one.

is this yours? You can stop the video at an appropriate spot and see some details.

http://www.youtube.com/watch?v=uqXOu-GaRDQ

I looked at the Parts page with the number you gave and no picture. Great Bachmann.

Rich

[badkarma]

Yes, that is the same board. I saw that and I was afraid that I would have the similar problem he had, but it worked with my NCE power cab right off the bat. Only problem with the GP40 upgrade are the lights.

[richg]

Yes, that is the same board. I saw that and I was afraid that I would have the similar problem he had, but it worked with my NCE power cab right off the bat. Only problem with the GP40 upgrade are the lights.

Since the LED's are part of the decoder, go up near the top of this page and look at the EZ Command CV list. Since the front and rear lights do not work, that tells me it is the decoder.

I have the Power Cab. Do a decoder reset. CV 8, enter 8.

Rich

[badkarma]

Thanks guys. It's a bad board. The meter test failed on the board for VDC check. The 9v test on the LED worked like a charm. I replaced the board with another brand decoder and all work great. Thnx again. I started another topic for the Dash 8-40cw.

[richg]

Thanks guys. It's a bad board. The meter test failed on the board for VDC check. The 9v test on the LED worked like a charm. I replaced the board with another brand decoder and all work great. Thnx again. I started another topic for the Dash 8-40cw.

Good troubleshooting. Great that you cam back. This might help someone in the future.

Rich