Lionel SD 70 A/C Regulator trouble

amosOGR Forum Member

Hello! I have a few Lionel SD 70'S that have a/c regulator trouble and of course they are no longer available. I learned of this a little over a year ago. I decided just to "sit " on the issue for a while and see if an alternate for the a/c reg was developed or a work around was made. I've been searching recently and found one post that talked about either a work around for the a/c reg or a "chuffer??" type unit to replace the existing smoke unit? The post did not go into any detail of either the work around or this "chuffer" unit. I'm very interested in more information on how to get my SD70'S smoking again. Smoke is one of my favorite features when running my trains. Thanks so much!

3/8/242:43 PM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

If you're talking about TMCC models, you can swap the resistor in the smoke unit for a 27 ohm unit and wire the smoke unit directly to the smoke connection on the motherboard. You will also want to wire it through the smoke switch so you can manually turn off the smoke. You remove the regulator totally with this method.

FWIW, the "Chuffer" is for steam, and it doesn't replace the regulator: Super-Chuffer II

3/8/244:16 PM

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martindOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

I have a Lionmaster sd90 with smoke problems and did the revision that John suggested, and it now works great. The hardest part was to solder to the motherboard.

Marty

3/8/245:02 PM

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amosOGR Forum Member

These are Legacy model trains. Is anything available for these?

3/9/245:55 AM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

@amos posted:
These are Legacy model trains. Is anything available for these?

You're out of luck with early Legacy. If the regulator has croaked, there is no replacement available, and no work-around either.

This is why we ask people that are posting to post actual product numbers, that way we don't have to guess about the answers.

BTW, the above answer was based on early Legacy with the modular boards, R4LC, DCDS-J, etc. If you have a later model with the RCMC, it may be a different story. Again, without the exact model, I'm just guessing.

3/9/2410:14 AM

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amosOGR Forum Member

The number is 6-28287. It would be awesome if somebody had a few new "old stock" regulators . I know they could be bad as well. It seems someone would be able to repair these regulators by now. I miss seeing the smoke on these locos. I find it incredible that Lionel has stopped supporting these locos. I'm think of trying out MTH or Williams. I appreciate your help greatly, John.

3/10/247:40 AM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Well, I did something to fix a couple of mine. I found that usually the Legacy regulator fails and just puts out a very low voltage. Not enough to generate smoke, but enough to be sensed so I had command control of the smoke. I added a little board to sense the anemic output of the broken regulator and switch a relay. Then I changed the smoke resistor in the smoke unit to a 20 to 27 ohm resistor.