Lighting Issue on Lionel Diesel

Interesting... I was working on a similar vintage Soo line SD-40 and lost half of  my lights...It had the same spring contact pad interface. I used jumpers and the lights would still not come on... swapped out the R2 board and that was the issue...

Did you press AUX2 by accident?  That will turn out the lights.

Thanks Guys but no.

The board here is R2LC 08

What does the R2 board control?

All other functions work except the front electrocoupler.

Thanks for the help.

Dave

The R2LC board controls the lights, electrocouplers, and smoke directly.  It also sends the serial data for the sound synchronization and the PWM signals to the motor driver to control the motion.

So is it possible John for the R2LC to fail in one area and still perform  the other functions?

I have no front coupler and no lights.

But everything else works.

Thanks

Dave

I would pull the motherboard and look for burned traces.  Also a very common issue.  The age of your locomotive puts it in the right time frame.   Swap the two wire coupler plug front to rear and see what you have.  If you have one known  good coupler output, use it to test both couplers.

It's certainly possible for the R2LC to fail in any one of those areas.  There are five triacs on the board, they can be burned up by a momentary short individually and kill that function.

I have looked for"burned traces" on all the boards and find none.

Can a board fail without showing any signs of burned traces?

JDaddy said that he lost half his lights and a new R2 board fixed the issue.

So,  I am assuming that the failure of an R2 board could not only fail in one area but also only fail in part of that area.  ?

Appreciate the help Guys

Thanks

Dave

It's actually very common for one or more triacs on the R2LC to have failed, usually do to shorting the output momentarily, and to look perfectly normal.  I've had R2LC's with up to three triacs dead, and of course the associated function didn't work.

When in doubt, throw in a known good R2LC and see what you have.

Just for chuckles, I'd first check the wiring to the lights.  Apply around 6V AC to the lighting circuits and see if the lights light or you have a short.  If you put a new R2LC in and you have a lighting short, you'll need another R2LC.

No spare parts Marty and switching over to mainly Legacy.  I do have 2 - TMCC missile launch locos.  I checked the parts info with Lionel and the boards are entirely different.

I applied the 6 volts AC John as you suggested.

I have lights........there are 2 negative and 2 positive springs.  One set activates  the front and the other the rear.

Dave

My vote has to go with either the R2LC or the wiring on the chassis.  Make sure with the R2LC removed that all the lighting outputs on the springs don't connect to anything like frame ground or rollers.  A pinched wire could be the issue here, check if there is any wire damage.  Also, using the meter measure from the lighting contact springs back to the R2LC connector, pins 9 & 10 are the rear lights, and pins 13 & 14 are the front lights.  There should be continuity all the way back.

If all those checks pan out, I'd replace the R2LC.

If you have a Lionel Tech close by, give the R2 to him to put in his board tester.  You will know everything in seconds.

I cannot find any damaged wires or anything for that matter that might cause this from a wiring angle.

So Guys...........I have a lead and will be visiting a qualified Tech 2 hours from here to test these boards.

I will report back with findings.

Appreciate the help and thanks again

Dave