6-38041 Burnt Board

It blew the smoke triac. Unless you somehow- beyond the fact most all smoke fluids are non-conductive- in and of itself smoke fluid was not the cause.

You somehow shorted the resistor or wiring to frame ground.

I would find and fix the short before replacing anything.

Then, that R2LC can be repaired at the component level or could b replaced by another R2LC or R4LC and just programmed for the correct type code when setting the ID.

Again, R2LC TRIAC outputs are often replaceable.

@PaperTRW posted:

It's been awhile since I've ordered replacement triacs for repairing LCRU, R2LC and R4LC boards, and the parts I've ordered previously are now deemed obsolete.

Does anyone know suitable replacements, preferably from Digikey, for the smaller MAC97 TO92 lighting and coupler outputs for these boards?

Also, what's the right replacement for the larger smoke unit triac? I've seen recommendations for the 2N6071A, 2N6075AG and 2N6075BG, but am unsure if one is better than another.

Many thanks-

TRW

Also in that topic https://ogrforum.ogaugerr.com/...73#70974704561309173

That does not look like smoke fluid film that got cooked, that looks like charred radio board to me, …..looks like the portion of the board that controls the smoke…..don’t be surprised if you do fix the smoke unit you still don’t make smoke….good news is, if it’s still running, at least it didn’t French fry everything!..

Pat

The how it could have failed.

@Vernon Barry posted:

It blew the smoke triac. Unless you somehow- beyond the fact most all smoke fluids are non-conductive- in and of itself smoke fluid was not the cause.

You somehow shorted the resistor or wiring to frame ground.

I would find and fix the short before replacing anything.

Then, that R2LC can be repaired at the component level or could b replaced by another R2LC or R4LC and just programmed for the correct type code when setting the ID.

Again, R2LC TRIAC outputs are often replaceable.

Also in that topic https://ogrforum.ogaugerr.com/...73#70974704561309173

Wow I did not think about the board going bad. That makes sense now. How would I go about finding the short?

That amount of board damage means you will need a new R2LC-C08 or equivalent, I don't think you can replace the smoke triac in that one successfully.

@gunrunnerjohn posted:

That amount of board damage means you will need a new R2LC-C08 or equivalent, I don't think you can replace the smoke triac in that one successfully.

Is the R2LC board all I would need to replace the current one?

Well, you need to fix whatever was shorted and smoked the triac in the first place, then put the new R2LC in.

This came up once before. Another member had the resistor burn through the fiberglass insulation that's wrapped around the whole length, and short out where passes through the metal puffer bowl.

With no fan, these old units get rather toasty at command voltage.

I have one of these and rebuilt the puffer, tried it out and then shut the switch off.

I'll run smoke when I have it upgraded to a fan unit some time in the future

I don't think I have any currently in service locomotives with a puffer, any that had them got retrofitted with a fan driven smoke unit.

@gunrunnerjohn posted:

Well, you need to fix whatever was shorted and smoked the triac in the first place, then put the new R2LC in.

How do I go about finding the short? Sorry for the questions I am new to this

Well, start with an ohmmeter, and then I'd trace the smoke wire all the way to the smoke unit.  It should go though the smoke switch on it's way to the smoke unit.  From the looks of the triac, it seems clear that a direct short to the frame happened and cooked that part.