Norfolk sd 70 -need some help

Hi Amos,

Did you get any flashing cab lights before your smoke unit stopped working?  If you did, and reset the loco more than 3 times it is possible that it has been disabled. (There should be a note in the manual to this effect if it is applicable.)

It is possible to re-enable the smoke unit by doing a full reset on the locomotive, but this won't fix things if the initial problem still remains.

I had a smoke unit that 'failed' because it hadn't been put together properly and this caused fluid to be deposited directly into the fan motor and circuitry. Once I had fixed this, and cleaned up the mess I was able to get it working again after a complete reset.

Thanks but the flashing lights don't apply here. I have that on an ac6000 but not on the sd 70. Thanks.

well, I spent a substantial time testing today.5 terminals on a/c smoke reg.

#5 does NOT send power to smoke unit when requested

#4 good ground for a/c smoke reg.

#3 gets power from track rollers as soon as "smoke on " is initiated.

#2 good ground for smoke unit

#1good serial wire from a/c reg. to r4lc board.

This thing has flat out beaten me so far. OH yes, I did reprogram for features multiple times. I don't know how to tell if the a/c reg is getting the signal on the serial line or how to test the a/c reg. itself.

Looking at your AC reg with the wire labeled S on your left, here is the wiring.  The S wire goes to pin 24 on your R4LC board.  This carries serial data and tells the reg to turn on/off.  Check for continuity on this wire first.  To the right of the serial wire is the AC (chassis) ground.  To the right of that wire is the AC (pickup rollers) hot.  This wire connects to the center post on your smoke on/off switch.  The other end of the switch with the wire goes to pickup rollers.  Check for continuity here to determine that you have continuity from the rollers to the switch and from the switch (when turned on) to the center wire on the AC reg.  The next wire to the right of the center wire is smoke unit ground.  Last wire to the right is the smoke unit hot.  Like before, check to be sure you have continuity on all these wires and where they go and come from.

Next set your meter to ohms.  You should read 6 ohms for the element to be good.  Acceptable readings are 5.4 to 6.6 ohms.  Looking at your smoke board you will see three contacts together.  The center is ground and the outer contacts are both hot from the center wire on your AC reg.  The fan motor gets 5VDC from an on board reg. 

One last thing, if everything checks out and it seems like you know very well what you are doing, check the voltage at your smoke unit (ground and hot) and you should see 9-12 VAC if the reg is working.   If you do not have that voltage and you have checked everything, you have a bad AC reg.  It is not uncommon.  I have run into a few.

On your question on how to tell if the serial wire is working, just try other engine features and that will tell you.  If everything else works, and no smoke, bad reg would be where i would place my bet.

Amos, I know you are using your continuity meter for your checking.  I run into several guys who state they check wires and they are good.  When I ask how they checked them they will say they look at them.  All wires to be checked in any repair should be done with a continuity meter.  A cheap tool and worth it's weight in gold sometimes.

Let us know how you do on this.

Thanks Marty. The little list I made is indeed the checks you suggested I make. I also did them with a meter-no, looking at them won't do-all you see is the casing,not the actual wire.

 I see that the wire from serial port 24(r4lc) splits ofF from the mother board and one link

goes to that board directly behind the front motor.  That makes me wonder why. Any how, I'll order a new ac/reg. and see what happens.

  The wires all check good. The a/c reg never sends voltage to the smoke unit. Hopefully I'll change that.

 Thanks again, Marty.

she is talking about a diagnostic feature that was added to late model Lionel engines.
.

Yes- I do have that feature on my

ac 6000. It's in the manual. Basically trouble codes for the smoke system.

Thanks,and as a matter of fact I intend to use as much of the new pigtail wiring as possible.