JLC Big Boy smoke unit

I had the same issue with mine years ago, ended up being a bad crimped terminal plug between the smoke unit and motherboard. Id check there.

The smoke unit in question is a 6 Ohm model that Lionel stopped using several years ago - it was a prolific smoker used in early Legacy engines like the FEF-3 and GS-4 but prone to blow the AC regulator. Lionel later recommended substituting an 8 Ohm resistor. I recall that for some length of time after that, a replacement PCB as opposed to the entire smoke unit assembly was available but unfortunately I no longer see that in Lionel's replacement parts pages.

I am not sure that there is any engine-specific logic on the PCB that would prevent substituting another smoke unit if you have to - hopefully someone more expert can opine on that. However, I have worked on a number of these and the PCB itself seldom fails but a component on it may have gone. I can't guess which one it might be because don't quite follow where you are measuring the power to the board and resistor and getting a track voltage reading. I suppose it's possible that only the resistor has gone and you might want to open the unit up to have a look at it. 

First off, that's a dumb board, so there's nothing to prevent you from replacing it, no logic on the board.  However, unless the board is burnt badly, you can simply replace the resistor with an 8 ohm one and then fix whatever is preventing the resistor from getting power.  Replacing the smoke unit will be a lot more work than fixing a simple problem with the one you have.

Some close-up pictures of both sides of the smoke PCB would help us help you, I don't have one of that particular model to look at.

Thanks for all your replies, I'll try to take them in order.

BRUK, I checked all the plugs and wires, everything looked good. 

HANCOCK 52, If I can get the pictures up there is one of just the male plug that I disconnected then connected to the red and black wires of that plug, when track power was on (whatever voltage) it was constant, I think it was AC voltage. Although the resistor looks bad it still measured 6 Ohms.

GUNRUNNERJOHN (like the name), I hope I can get the pictures up for you, it's such a nice engine I would really like it to smoke.

Thanks again.

I don't see any physical damage to the PCB, and since the fan works, there's nothing on the PCB to prevent the smoke resistor from heating.  I can see the traces from the GND & HTR pins and they're fine.

Let's start with the basics, measure the resistance of the smoke resistor and tell us what you get.  With this unit, I'd put the 8 ohm resistor in, and also you have to make SURE those screws/nuts are tight, that's a frequent cause if issues.  another thing, make sure when you reassemble it that the smoke resistor does not touch the sides of the smoke chamber.

You don't need a new smoke unit.

I just had a problem with a very similar smoke unit on my Allegheny.  John helped me and told me to replace the resistor with an 8 ohm and new wicking.  Works great!!  Smokes really good.  His insight was so helpful.

Hi John, and everybody else.

The old resistor was 6 Ohms, but I did have a brand new 8 Ohm resister, installed it as per your directions, screws tight, resistor not touching the chamber body, did not heat up, also checked voltage at the resistor mounting screw heads, got nothing

What do you get at the connector?

I suspect the regulator module.  With this smoke unit model, the heater voltage doesn't power the fan, the smoke unit gets 3rd rail direct to power that logic chip that controls the fan.  The smoke heater is powered directly from this module, which is almost surely bad.

The only connector I checked was the 4 pin that goes to the PCB, I only checked the red and black wires, that's where I get whatever voltage I put in up to 20 volts (red goes to on, off smoke switch, of coarse black to ground one white wire goes to a cherry switch and the other white wire goes to the AC regulator).

Well I have that AC regulator #691ACRG103, I purchased everything I could for that engine, I hope it's not to bad to put in, I'm 71 yrs. young and I have essential tremors, (the shakes) makes it very hard for me to solder.

Correct, track power, ground, smoke element voltage, and serial data come to the smoke unit.  You're missing smoke element voltage.

Installing the regulator is usually accomplished by clipping the wires near the old one.  Then you can splice the wires together, much easier than soldering PCB pads.  There are typically two black wires (both ground), but sometimes only one is used.

• Black (frame ground)
• Red (Track power)
• Brown (R2LC serial data)
• Black with brown stripe (smoke element power)

Click on graphic to expand.  This graphic is close, but the newer smoke units got the chuff from the serial data, thus the chuff switch isn't connected to your smoke unit.

Sorry, this is later than the other posts above so has been overtaken by them but I include it for completeness.

Fortunately those AC regulator modules are still available from Lionel (and now I note that you have one already).

This is unscientific and I don’t want to confuse the issue, but I recall a thread  a couple of years back where we were discussing this generation of Lionel smoke units and this PCB was mentioned, which is still available from Lionel but you have to search under replacement part number (not product number) for 691SSMUK02:

The part number printed on the part, which I have got from Lionel in the past and used on one of these units, matches your photo above. But replacing the PCB won’t restore operation if it’s the AC regulator that has gone. 

The PCB is available, but it's pretty clear from his photo that there's nothing wrong with the traces that go from the connector to the smoke resistor.  That being the case, it's pointless to replace the PCB, that isn't were the problem is.

Well John I think your on the right track with the AC regulator, the old one had 4 wires and was grounded on the frame with a screw, see picture, the regulator was a little loose, you can see burn marks on the screw hole, also the replacement regulator has 5 wires, (see picture) two of the blacks look the same, is it going to matter which black goes to frame and which goes to existing black on old regulator. thanks for the graphic I'll print that out, and maybe pick up that board if it's still available. 

IMPORTANT!  The regulator triac MUST have the isolation from the chassis, if the plastic insulating bushing and insulating pad is missing, you'll cook the new one!

gunrunnerjohn posted:

IMPORTANT!  The regulator triac MUST have the isolation from the chassis, if the plastic sholder washer and insulating pad is missing, you'll cook the new one!

The last one of these I got did not look like the Lionel replacement parts page image copied above. In particular, all the components were within the black shrink wrapping (no triac sticking up outside of it) and there were five wires instead of the four on the original part. The part I got looks exactly like the OP's replacement part and is really fairly small. 

I still put some insulation between the shrink wrap and the frame and connected the four original wires leading to the old regulator to what I worked out were the corresponding outputs on the new one. I can't now remember exactly how I dealt with the fifth wire but GRJ's diagram above looks familiar. Anyway, it worked.

Well thanks guys, this is a big help, it looks to me like the two black wires both go to ground, that being the case, I'll run one to the original black from the old regulator and one to frame ground, don't know what else to do there.

John, I know what you mean, I once missed an isolation pad on a board for another engine "poof" learned the hard way.

Thanks again, this is going to be awhile, but I'll definitely let you the outcome. 

Yes, as I said, there are two grounds.  Only four wires are needed, I think the two grounds were there to make wiring easier.

Most of the TMCC ones are as Hancock52 states, totally shrink-wrapped.  However, later TMCC and early Legacy started bolting the triac to the chassis to aid with heat dissipation to try to slow down the excessive failure rate of this module.  Not sure how successful they were, but that's the rational for exposing the triac.

FWIW, the metallic side of the triac normally faces down on the chassis on top of the insulating pad, then the insulating bushing goes through the hole to insulate the screw from the metal base and into a threaded hole.

Thanks John, I'll let you know how I make out.

I have the new AC reg. wired in, it does smoke,      "a little"    I'm using Legacy control, the off, low, med, high, does not matter what setting I use I get the same results, a little smoke at very low speed, anything faster you don't even see it,  NOW, if I keep pressing for more smoke (med and high) as fast as I can it will fill the room with smoke, but as soon as I stop pressing the button it goes back to a little smoke, pressing and holding the button down does nothing. Any ideas?

That's the symptoms of the smoke regulator in it's early stages of failure.  They typically start dying by not controlling smoke reliably, then it progresses to where you either can't control the smoke at all, or there's simply no smoke.

Since this is a new part, I am a bit surprised you're having this issue.

Yes it is a new one, the old one before it died put out very little smoke like this one but it did not respond to pressing the more smoke button like this one.

Tomorrow I'm placing a order to Lionel, not sure if I'm going to order another regulator, I want to double check what I did first.

Thanks John.

Make SURE the four wires are connected in the proper places.  I suspect they are, if you connected the smoke (brown/black) to the serial data, things would be a lot worse!   That was a bad choice of colors by Lionel, don't know what they were thinking.  Having two wires that look brown is pretty dangerous, swapping them and nasty things happen all over the place!

If you just matched all the wires up, being careful with the two brown ones, not much else to say.  That's all there is to installing the regulator, other than bolting it down with the correct insulating hardware.

I checked all the wiring, look right, I also went back to a 6 ohm resistor, of coarse it got better, you can at least see some smoke at speed, would there be a problem installing a 4 ohm resistor if there is one, would it pull to many watts.

Go back to hancock52. Lionel recommended going to 8ohm instead of using the original 6ohm. Going to 4ohm would most likely ruin the board portion that drives the smoke. 

The reason they went to 8 ohms is 6 ohms was overloading the board and killing them.  Going to 4 ohms would probably kill the regulator on the spot.

There is something else going on, as I can use the 8 ohm resistor with the voltage regulator and get very decent smoke.  I think you need to spend the time to do a tune-up on the smoke unit.

To the OP, you can't go wrong listening to the fellas on the forum; they helped me thru rebuilding the main smoke unit on my Big Boy; got all my parts from Lionel but I replaced all of them - resistors, PCB, fans, reservoir, wadding - cost a bunch but unit now works great and I know how to rebuild a unit - no worries.  For some tips maybe you can look at my trip: https://ogrforum.ogaugerr.com/...opped-working?page=1

Based on my own experience of these units, and what you report about what you have seen, a tune-up of the unit itself is certainly worth doing, as well as checking simple potential faults like the alignment of the stack and whether there is any fluid or wadding blocking the output funnel. These smoke units came stock with the pre-cut pads that Lionel no longer sells as replacement parts and the resistor was installed well down into the wadding material but with no blockage of the channel between the fan housing and the smoke chamber. With a 6 Ohm resistor mine smoked like nothing I have ever seen. When I eventually had to replace the wadding with ordinary rope wadding shredded and packed into the chamber, the smoke output went down somewhat but was still copious by Legacy standards. In one of my engines, I did not replace the 6 Ohm unit with an 8 Ohm unit but I have seen it done and the smoke output was not greatly affected - at least where the unit was otherwise correctly packed and had been fully charged with smoke fluid.

However, I can't help thinking that there might be something else that needs adjusting and in particular if you are only seeing a marginal difference between the original and replaced AC regulator. Have you tried an engine reset? This is an RS5.5 engine so it seems it has the early modular boards and I wonder if something has gone wrong with the settings.  I don't know how to diagnose these other than by trying a reset; someone more expert might have an idea. I guess you have to discount the possibility of a component on the PCB going bad if you are getting power to the heater. Have you measured what it is at the resistor terminals?

In terms of wiring up the AC regulator, I can't second guess what GRJ has said although I am racking my brain to remember what I did with the second ground wire. I might have tied it in to the other ground wire (see the diagram posted above) or simply cut it off as surplus to requirements. I do remember puzzling over this but I can't trace any thread in which I asked for advice on the forum. 

The two ground wires are tied together on the regulator PCB, so it's just an extra wire for wiring convenience.  As long as the one makes it to a good frame ground, the other wire is totally optional.

I don't think that this will add anything new but I post it for the sake of completeness.

The guidance I got on replacing the AC regulator came from Mike Reagan himself and was given back in 2011. He said:

"The AC Reg consists of 4-5 wires that need to be cut and spliced and soldered and covered with shrink tubing. The wire designations are on the PVCB, under the heat shrink wrapper. The board must be screwed to the frame and electrically isolated from the frame too."

I partly cut away the wrapper to see the wire designations and then sealed it up again. The regulator I got back then did not have the triac outside the wrapper any more than the ones I got later. 

Some of them are totally encased in the heatshrink, others have the triac hanging out to be bolted down for heat-sinking.  I have new ones in both configurations in my parts boxes.  Most of the Legacy ones went with the exposed triac, probably because they failed so often without heatsinking.

As for having to open it up, I just match the spacing of the wires to the standard pinout, I've never seen one that has a different layout.

Hi people, thanks for all the replies, I did put in a new resistor with new wadding material, I think it's OK, if I keep pressing the increase smoke button I can fill the room with smoke, soon as I stop repeatedly pressing the smoke button it goes back to almost nothing, YA, I did have very very little smoke with the old regulator makes me wonder, but I can't figure it out, I used the ground wire (on the 5 wire regulator)  that seem to match the ground on the old (4 wire regulator) left the second ground detached, then just for kicks I grounded the second ground wire to the frame made no difference, had to try.

I thought the 4 ohm would be pushing my luck, but I had to ask.

Well I guess a little smoke is better than nothing, which is what I started with, and if I want to keep pushing the increase button I can have a lot of smoke.

Thanks again.

I'd have to see that one to figure out what's going on.  I have seen regulators that do something similar, but a new one shouldn't do that.

I've never had that issue. And if GRJ says it's likely an AC Regulator problem I defer to him. But I still wonder if it could be a software/control board issue as what you describe sounds like defaulting to the low smoke setting after you ramp up the smoke via the remote.

That prompts me to ask if you are using a CAB2 for control, which version of Legacy you are running and what settings you are using for this engine? I have noticed a couple of odd things about the latest version of Legacy when running some TMCC/ERR engines in that the commands don't execute exactly as they did under older versions. That really should not happen with a Lionel RS5.5 engine like yours.

Defaulting to low smoke after trying to ramp up is a excellent description of what's going on, I'm using CAB 1.61 and BASE 1.60 legacy, settings, STM, LEG, LRS, and I did do a factory reprogramming, but the manual says it's for TMCC. Hope this helps

Reprogramming is not just for TMCC.  Did you follow the manual instructions to reset the locomotive?

Sadly, when I've seen the smoke regulator forget the smoke settings, it's usually a bad regulator.  I have seen the same symptoms, and it's always been a regulator replacement required.  FWIW, the smoke heater on this model isn't affected by the R4LC as the smoke output of the R4LC isn't used, or is used for the cab light.

My Legacy system has been at the latest version since it came out, I've never had it cause this kind of issue with any locomotive.

Those all seem to be correct settings; I don’t see anything in the Legacy v 1.6 manual that indicates any special/different settings for this engine. There is an option to enter the RS settings as RS5 but your manual describes this as a Legacy Railsounds engine. This is a JLC engine; I don’t have it but the couple of JLC engines I do did not come with an orange module and there’s no reference to one in your manual. Unless there’s some quirk about RS5.5, I can’t see that the settings are incorrect.

Process of elimination: have you tried starting it up in conventional and seeing if the smoke volume is greater at higher voltages?

I notice that there is a wiring diagram for this engine, copied below:

It may make no difference but this (top left) shows (1) the AC Reg. second ground connection not used/clipped off and (2) the AC Reg. model as 691-ACRG-100. That model is listed as obsolete and unavailable at Lionel, with no specific alternative listed. There was another model, which I think is also designated obsolete, 691-ACRG-101, still available at Lionel but the alternative to that is the one you and I both have listed as -103 (S03 Code). That did work with my version of this particular smoke unit.

At this point, I wonder if the answer is buried in Lionel’s own knowledge base. Mike Reagan occasionally posts here and a shout out to him @Mikado might shed some light on this. I believe he is still doing great repair work.

JGR, I reprogrammed this engine to the letter as per your post, there was no difference. In conventional mode I saw nothing, but full speed is to fast on my layout, I tried CAB 1, different RS, and pressing the + button in any of those modes does not give me more smoke, I have a second Legacy controller I tried, no difference there. I'm thinking of getting another regulator to try, a spare would not hurt anyway. thanks for the wiring diagram I'll hang on to that, I'll contact Mike to see if he wants to contribute to this problem.

Thanks

I have come to find out that the differences between some of the AC regulators aren't that great.  If a specific one is unavailable, use a different dash number, usually works just fine.  I believe all of them will deal with an 8 ohm smoke resistor.

Just a stretch here but if you have an extra R4LC (S02) it might be worth a try; lots of good info from GRJ and Hancock; maybe even an R2LC swap; again reaching out of the box because you get good smoke with the boost.  Just odd; good luck; Falcon70

Once again, with the smoke regulator, the R4LC doesn't get involved in the smoke heater operation at all.  I suppose since the R4LC receives the serial data it might affect it, but I'd think it would also affect sounds, chuffing, etc.

Just a couple of thoughts here as I have been following this.

Could the issue be poor continuity in the on/off switch to the voltage reg board?  Could it be limiting the current available to generate the correct amount of heat?  I would try to jumper the smoke on/off switch to eliminate this as a possible cause.

Also, wasn't there a change in where the on/off switch was placed in the circuit over the years?  I seem to recall the smoke on/off switch used to be in the brown/black + wire going to the smoke unit.  In latter engines, the switch was installed in the red + power feed to the voltage regulator.  Should not make a difference, unless the smoke switch is off and the voltage regulator was being used for some other power needs.

I'm still racking my brain as to why there is full smoke when boosting power to the smoke unit and then it returns very little smoke when you stop pressing the smoke boost button.  Isn't there a setting for high, medium or low smoke output?  I would have to confirm this setting gets reset with an engine reset as I have never tested. Does it matter if you use a Legacy or Cab-1 to make the smoke level changes?  I have had times when I had to use one controller vs the other to get things back to "normal".

I would also agree that the smoke unit needs to be tuned.  I have had issues with the batting obstructing the air flow too much, causing poor smoke output.

John, If I am correct, the voltage regulator board accepts the boost smoke signal and then puts out more volts to the smoke unit.  Could you confirm this?  The other possibility is the voltage reg board is controlling/limiting the current.  Again, I have never tested this to confirm.  I have never had a voltage reg board fail like this.  It was either all or nothing.

Dave

I've seen a number of different failures.  When they're working properly, they step up from "low-medium-high" when you press the smoke key repeatedly.  There's no "boost" like in TMCC, any boost is applied automatically by the Legacy logic.  Somewhere there is a chart that I believe Mike Reagan posted once that showed the sequencing of the Legacy smoke operation.  At each upward step there was a brief automatic "boost" before it settled at the new setting.  If the smoke regulator is doing what I've seen some of them do, it may be forgetting the "high" setting and when you step back up it's applying the high boost momentarily.

FWIW, the Legacy smoke units also respond to the TMCC regulator key sequences, might be useful to try those and see what happens.

AUX1, AUX2, 9, H, then AUX2 again to save the setting.  This sets the smoke volume to high.   
The L,M,H, buttons are the momentum buttons at the bottom of the remote, they also select smoke volume.

Setting smoke volume on TMCC locomotives with smoke regulator.

- AUX1
- AUX2
- 9
- <vol> (see below)
- AUX2

<vol> is the smoke volume setting, L, M, or H.  The L,M,H, buttons are the momentum buttons at the bottom of the remote, they also select smoke volume.  
When you're done, you will probably want to set the momentum back to your desired setting as setting the smoke volume affects that too.

Thanks for the reply Dave, I'm thinking if the on / off switch is limiting voltage I would not get all that smoke when I'm pressing the button for more boost, I did rebuild the smoke unit, if I want I can smoke me right out of the room.

I tried the TMCC settings, just stays on low smoke no matter what I do, no boost, no nothing. Maybe I should have mention this before, as soon as you turn track power on the resistor comes on (low)  you can turn it off at the controller or the switch under the cab it will shut down, I have some TMCC engines that do the same thing, so I thought nothing of it. I ordered another regulator, but what bothers me is the old regulator did the same thing, it had low smoke all the time, I did not try to push the more smoke button repeatedly so I don't know what would have happen. I bought the engine used, it's very nice, but who knows what happen in it's other life, maybe that's why they sold it.

The regulator not listening to the smoke commands, assuming it's wired correctly, is almost surely the actual regulator module.  Like I said, I keep a stock of assorted regulators, I see a lot of them go south.

Artson posted:

Maybe I should have mention this before, as soon as you turn track power on the resistor comes on (low)  you can turn it off at the controller or the switch under the cab it will shut down, I have some TMCC engines that do the same thing, so I thought nothing of it. I ordered another regulator, but what bothers me is the old regulator did the same thing, it had low smoke all the time, I did not try to push the more smoke button repeatedly so I don't know what would have happen. I bought the engine used, it's very nice, but who knows what happen in it's other life, maybe that's why they sold it.

I believe that the low smoke on start up is characteristic of TMCC and early Legacy. I forgot about this until I recently got a TMCC engine where the smoke remained on even after a shutdown; I always had to shutdown the smoke manually separate from the Railsounds system. My early Legacy FEF-3, with the same smoke unit as yours, behaves just like this. The smoke is on whenever the engine is on a powered track. By that I mean that there is power to the heater; the fan does not run until the engine moves.

As GRJ is saying that the AC Regulator is not retaining the smoke settings I can't second guess that. Why this is the case - well, that is another matter. I do know the chart he is referring to; I believe it is duplicated/explained in one of Mike Reagan's smoke unit videos. Even if your engine is used, any original defect or one created by use should be capable of diagnosis. The smoke units themselves are not rocket science.

What I certainly didn't remember is the command sequence GRJ sets out above for adjusting smoke settings. It would be worth trying those.

Failing that, maybe a new regulator will cure this issue. I hope so. I have seen so many variations of Lionel smoke units that honestly it is bewildering to try to figure them out. This is where I wish Lionel would explain, or have already explained, somewhere how the different variations actually function, particularly as they won't do repairs themselves any more.

Like I said before I have a new regulator ordered, JGR, keeps saying about having the wiring correct, (he's right) so I went back (again) with the help of the wiring diagram,  (thank you) and not knowing anything about electronics I can only tell you what I saw,  the black wire or wires go to frame ground, the red goes to the on / off switch, the black and brown goes to the smoke unit, and the brown goes to a yellow wire nut which also contains two blue and one purple and white, one blue goes to a 3 prong plug on the mother board with the R4LC RCVR BRD attached to it, next to that plug is j4, grd /grd ser, the other blue goes to a 10 pin plug on the DCDS-J motor driver board with j4 next to it and the purple and white looks like it goes to the I.R. transmitter, this is the way the old regulator was wired, I did not change it, if you think this is correct I'll wire the second new regulator the same way.

For my part, I can’t see any problem with your wiring. In my case, the first time I replaced an AC regulator for a smoke unit of this kind I checked the original wiring and spliced into that after I had checked what to do with Mike Reagan, which only happened after I had looked at various diagrams. It worked and that repair has held good for 8 years although only with intermittent running time. 

I hope this cures your problem!

The regulator wiring sure sounds correct.  FWIW, the smoke regulator SHOULD remember the last smoke settings.  As stated previously, the smoke unit is actually energized by a pulsing current whenever the power is on the track, even if you have previously turned smoke off using the TMCC remote.  Obviously, if you turn smoke off with the physical smoke switch, that no longer happens.  Whenever you turn smoke off using the TMCC remote, the smoke reverts to the pulsing action.

In a disappointing test, I actually tested a new smoke regulator, 691-ACRG-E01 - AC REG BOARD / GENERIC.  The smoke on/off works fine, however the smoke volume settings don't appear to function at all. 

For my testing, I put a 5W 10 ohm resistor as a load on the test set, it was sitting at around 120C +/- a few degrees at idle with the smoke off and the smoke regulator pulsing the smoke resistor voltage, the temperature drifts up and down several degrees as it runs.  Note that the temperatures I'm reading have no real relationship to what you'd actually see in a smoke unit, I just want relative readings based on the smoke settings.  I'm reading the resistor temperature with a Type-K thermocouple clipped to the resistor.

I used the smoke volume controls to set low smoke, AUX1, AUX2, 9, L, AUX2.  The temperature stabilized at around 164C when it stopped moving.

I then used the smoke volume controls to set high smoke, AUX1, AUX2, 9, H, AUX2.  The temperature never moved from the 164C I had with the low setting.

VERY DISAPPOINTING!  I have to wonder if the smoke volume settings that are published are actually correct! I have actually seen these make a difference in the past, I don't know why I get the results I do here. I even tried a second and third regulator, same results. I know the regulator is listening to the serial data, it turns the smoke on and off on command.

The smoke setting control keystrokes came right from the horse's mouth, This is from the User's Manual for the Lionel 6-38081 JLC Allegheny.  I was checking to make sure my previous smoke control keystroke statement was 100% correct.  I've seen this same description in several manuals, though many of the manuals for engines with regulators do not contain the setting instructions.

Test set connections to the smoke regulator and test resistor.  The tweezers are clamping the type-K thermocouple to the resistor to take the readings.  The bulb is just there to provide a visual reference to what the smoke unit heater is doing.

Thanks John.  Very interesting in that there was no difference in output.

Thinking about your statement, "the smoke reverts to the pulsing action".  Does this infer the pulsing action actually goes away when the smoke is "turned on"?  Or does the frequency increase so that it looks like a constant voltage (I would also guess there is a CAP in this circuit as well.)?  This goes one step further to ask if its the frequency (pulse rate) that is increased or decreased depending if you are at the Low, Medium or High smoke output settings.  The tests results could be impacted if the resistor may not be as responsive to the change in pulse rate of the voltage.  I do not have a scope available to test.

Do you have any suggestions on any further testing?  I would be more than happy to assist.

Dave

Smoke goes steady when it's turned on from the remote, it drops to pulsing when it's off, apparently to keep the element warm enough to get smoke fairly quickly.  This is the same thing that the Legacy whistle steam does.

The pulse rate doesn't change regardless of the smoke volume settings.  Truthfully, it appears for all the world as if it's totally ignoring the smoke volume settings!  I had a voltmeter and my temperature sensor connected to the test resistor, the voltage or the temperature didn't change at all.  The response of the resistor should be a non-factor, I'm sure they're not taking feedback from the resistor into consideration.

There is no CAP involved, there is a small microprocessor on the smoke regulator board that controls the action.

I'm going to dig out a different model of the smoke regulator and see if I get a different result.  I know some of these regulators do respond to the test sequence, I'm a bit befuddled as to why these don't respond like I'd expect.

Thanks!

Dave

Yes, many thanks. I don’t have the necessary gear to conduct a similar test on the AC Regulators I have or I would try it. 

The part number 691-ACRG-E01 is different from the ones we have been discussing. A quick search of Lionel parts does not disclose what vintage/kind of Lionel engines it was used in. I had wondered whether there was some important mismatch between the OP’s early Legacy Big Boy, which was supplied with an ACRG that is described as obsolete, and the parts that are available now, but that would certainly not explain GRJ’s test results

I finally received my parts from Lionel, another new AC regulator, rebuilt the smoke unit again, another new 6 ohm resistor, same thing, still stuck on low smoke, which is about nothing at speed, I just seem to be throwing good money after bad.                      I'm assuming the AC regulator is suppose to change  voltage to the smoke resistor, is there anyway to get a fixed voltage that would equal med / high to the smoke resistor, I have no need to adjust it, the fan works fine.

You should not be using a 6 ohm resistor in the smoke unit.  Years ago Lionel suggested changing to an 8 ohm resistor as the 6 ohm one was killing the regulators.

For TMCC it is easy to eliminate the smoke regulator, not so easy with Legacy as the R4LC code doesn't allow you to control the on-board smoke triac.

When I installed the first new AC regulator I used a new 8ohm resistor like you suggested, and it bearley worked, so I went back to a new 6 ohm resistor, like what was in it I think from new and it worked just a little better, but not much.                    So far, I have used ( 1 new AC regulator with a new a new 8 ohm resistor ) and ( 1 new AC regulator with a new 6 ohm resistor )  and I still have to push the high smoke button repeatedly to get any substantial smoke.    Any other suggestions ?                                                                                    Thank You.                                                   

I'd be looking at the power wiring to the smoke unit, something is amiss as I've had many through here with the 8 ohm resistor and they smoke just fine.  Whenever I get one with the 6 ohm resistor, part of the repair is replacing it.  I've never had a complaint.  I believe Bruk suggested checking the wiring in his first post, it was a good suggestion.