FWIW, when I have looked at thermistor placement on TAS and 3rd Rail units, it was nearer 1/8th than 1/16th. However I did not know before reading this thread that the heat transfer was through the wadding and it has to be saturated for this design to work correctly.
Hancock52, you mention an extra wire on the second one - what extra wire??
RickM46 posted:Hancock52, you mention an extra wire on the second one - what extra wire??
I only meant the extra length of wire forming the leads to the thermistor, not that there is a whole other wire.
Hancock52 posted:FWIW, when I have looked at thermistor placement on TAS and 3rd Rail units, it was nearer 1/8th than 1/16th. However I did not know before reading this thread that the heat transfer was through the wadding and it has to be saturated for this design to work correctly.
Since the Legacy system is a totally different design, that probably has little bearing, though I think that's what I see when I look at these. The TAS sensor was open-air, it didn't sit in the wick.
Per Jon Z in a previous post re my Legacy smoke unit: 'The temperature path for the element to the thermistor is through the fluid dampened batting. When the batting is not saturated, the temperature rises on the element, but the air between the thermistor and the element is a poor conductor of the heat, relative to a saturated batting material.
gunrunnerjohn posted:Since the Legacy system is a totally different design, that probably has little bearing, though I think that's what I see when I look at these. The TAS sensor was open-air, it didn't sit in the wick.
Agreed. I have just looked at an old TAS unit I have on hand and the thermistor was mounted above and slightly behind the resistor. The 3rd Rail units have the same basic design but with a ceramic-coated resistor. I recall that in one of those, when (per advice from Scott Mann) I moved the thermistor further away from the resistor, the unit smoked as you'd expect. He told me that at the factory they sometimes don't ensure the clearance is sufficient. It was originally within 1/16th inch and I backed it out to about double that.
Lionel's system is obviously more complicated and maybe has something to do with substituting plastic components for metal. Anyway, now the VLBB blowdown issue has gone to the top of my personal irritation list and I'll check it out next week.
Thanks gentlemen for the discourse and info; I have adjusted the resistor and thermistor to be the same as the old unit; gap is sitting at 1/16 inch; the first picture is the un-adjusted new unit; the second is the adjusted new unit. The adjusted unit matches the old unit.
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Folks, thanks to the help from so many gents on the forum, I finished building the front main smoke units - 2 chambers and fans; all new parts. Primed each wick with 70 drops of fluid; made sure I didn't overdo it by turning the unit up side down and looked to see if any fluid drained out - none did. I am working on a smoke unit document consolidating all that I learned for each component. Oh, yes, the Big Boy is back on the tracks and smoking up a storm. Its internals ain't factory anymore but it works; note the 10mm SS screw holding down the PCB.
Ran into a few assembly problems: the smoke unit funnel was pressed into the PCB to be un-removable and orphaned a mounting screw under it; one of the reservoir chassis bracket holes was not tapped; one other reservoir mounting hole for the PCB was stripped; one wick was 12 inches long - all others were 8.
Learned a lot: bought a whole bunch of parts and tools: namely a multi meter, Hakko FX888d soldering station, Hakko FX100 temperature unit, screw driver magnetizer, soldering tweezers (helped installing the 5 pin plugs into their recpticals), 20g, 22g, 28g, 30g wire, wire nippers, wire strippers, .5mm solder, Helping Hands work station, heat sinks, electrical tape, all the smoke unit parts I could get from the Lionel parts page, micro screws, 8 inch wick.
In the 2nd pic, notice the 10mm long ss screw to the lower left; got it from Micro Fasteners to use in a stripped hole.
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Now you're all set to go into the repair business! 
gunrunnerjohn posted:Now you're all set to go into the repair business!
Yeah, it’s all just a matter of having the right tools, isn’t it? 🔧🛠🔩🔬🍸
Hancock52 posted:gunrunnerjohn posted:Now you're all set to go into the repair business!
Yeah, it’s all just a matter of having the right tools, isn’t it? 🔧🛠🔩🔬🍸
Yep, spent a bunch on all the stuff; but, now I can overhaul my units; Mike R's service of the loco left it in factory condition and that provided a good base.
Tinplate Art posted:GREAT work and results! Of course, the "elephant in the room" is why could Lionel not have included a better designed smoke unit in such a premium, high end model in the first place? This question, unfortunately, is never answered!
He restored the unit to factory condition and it smokes great, so what do you recommend to be designed better? Seems like it works as expected after rebuild. Smoke systems have consume-able batting material, and they need serviced. Please don't confuse maintenance with design. And since you believe the smoke unit is not designed well, please explain what your expertise indicates is in need of improvement? Constructive feedback is always a good posture.
BOTTOM LINE: I am VERY GLAD the gentleman got his smoke unit repaired!
I've replaced a ton of MTH smoke unit wicks, so I can only assume you've not run these locomotives a great deal. I've never tried to quantify whether the MTH or Lionel wick lasts longer, but both need regular replacement.
Lionel got a big black mark with the run of bad fan motors, but I believe that's all behind us now.
Just sayin... 
GRJ: GOT IT, and THANKS! (smile)
Gents, am very happy to see the good ol Big Boy lumbering around the track again with everything working; especially since the smoke unit was fixed with my own 500 pound gorilla paws. Now, I am fat, dumb, and happy - a dangerous condition. I have destroyed a number of smoke units - usually either drowning or starving. I did starve the BB right out of the box using a micro dropper. Now, lesson learned; the object is to keep the wick saturated; hence, I will keep track of minutes run. There has to be a correlation between that and drops to replenish.
One last thing; the funnel to the heating elements on the BB has 2 chambers - one feeds the front stack, one feeds the rear. I think when dosing with a small number of drops, you are only wetting the chambers.
SantaFeFan posted:He restored the unit to factory condition and it smokes great, so what do you recommend to be designed better? Seems like it works as expected after rebuild. Smoke systems have consume-able batting material, and they need serviced. Please don't confuse maintenance with design. And since you believe the smoke unit is not designed well, please explain what your expertise indicates is in need of improvement? Constructive feedback is always a good posture.
Jon,
It is good of you to post here and I am replying with no small amount of appreciation; you have assisted me in the past (re: Acela). I don't intend to hijack RickM46's thread but since you ask . . .
Speaking as a pure amateur, it's difficult to comment on the current generation of Legacy smoke units without knowing why various design changes were made: plastic components for the smoke unit reservoirs (which in my experience don't hold up to ordinary maintenance disassembly because screw threads are easily damaged), air channels that require the fan motor to be wired the reverse of the norm (no change being made in the impeller design), pads instead of rope wicking, use of thermistors that can easily be put in the wrong position during factory or later assembly are examples that occur to me. All I can say is that up to the changes that were in the Legacy AC-9s smoke units, which I understand involved changing the code used to control their operation, later model Legacy smoke units just do not perform up to expectation and are not easy to maintain.
I have a feeling that most or all of the changes are related but explanation of this has been in short supply.
I will say that when the VLBB was issued, Mike R's video on its operation emphasized that the smoke units use up fluid rapidly. In mine, I have only ever used Lionel premium fluid and been careful to watch for signs that the fluid was getting low - which tends to happen after no more than about 10-12 minutes of continuous operation. Warning people off of overfilling smoke units (as the relevant owner's manuals all do) can itself create the problem of these units really not having an adequate fluid supply - particularly dual chamber units where there is only one filling point.
I for one would like to understand the theory behind the operation of these units.
P.S. I am nostalgic for the VL GE Evo smoke system, which for me always worked exactly as advertised!
Hancock52 posted:SantaFeFan posted:He restored the unit to factory condition and it smokes great, so what do you recommend to be designed better? Seems like it works as expected after rebuild. Smoke systems have consume-able batting material, and they need serviced. Please don't confuse maintenance with design. And since you believe the smoke unit is not designed well, please explain what your expertise indicates is in need of improvement? Constructive feedback is always a good posture.
Jon,
It is good of you to post here and I am replying with no small amount of appreciation; you have assisted me in the past (re: Acela). I don't intend to hijack RickM46's thread but since you ask . . .
Speaking as a pure amateur, it's difficult to comment on the current generation of Legacy smoke units without knowing why various design changes were made: plastic components for the smoke unit reservoirs (which in my experience don't hold up to ordinary maintenance disassembly because screw threads are easily damaged), air channels that require the fan motor to be wired the reverse of the norm (no change being made in the impeller design), pads instead of rope wicking, use of thermistors that can easily be put in the wrong position during factory or later assembly are examples that occur to me. All I can say is that up to the changes that were in the Legacy AC-9s smoke units, which I understand involved changing the code used to control their operation, later model Legacy smoke units just do not perform up to expectation and are not easy to maintain.
I have a feeling that most or all of the changes are related but explanation of this has been in short supply.
I will say that when the VLBB was issued, Mike R's video on its operation emphasized that the smoke units use up fluid rapidly. In mine, I have only ever used Lionel premium fluid and been careful to watch for signs that the fluid was getting low - which tends to happen after no more than about 10-12 minutes of continuous operation. Warning people off of overfilling smoke units (as the relevant owner's manuals all do) can itself create the problem of these units really not having an adequate fluid supply - particularly dual chamber units where there is only one filling point.
I for one would like to understand the theory behind the operation of these units.
P.S. I am nostalgic for the VL GE Evo smoke system, which for me always worked exactly as advertised!
I could write a book on smoke systems. Since the introduction of the RCMC system I designed, the smoke system controller and its subsequent tuning was my responsibility, and my nemesis. I spent many long days in China, at the design center, working various smoke bowl and assembly designs with the team. Making a better smoke system has been studied by the brightest folks I know of in the industry, there is not much more, if anything, left to improve. The current designs are pretty good if the smoke unit is built properly and maintained, and it should work nicely for some time.
I really can't comment more as I am not sure what would be confidential in an explanation of the design work to make these smoke systems function. I still have to respect the confidentiality agreements of the company I worked for, and I actually doubt a book would solve the problems 100%.
Still, the forumites are a bright group of folks. And as I stated - any constructive feedback means a lot to the designers.
SantaFeFan posted:Hancock52 posted:SantaFeFan posted:He restored the unit to factory condition and it smokes great, so what do you recommend to be designed better? Seems like it works as expected after rebuild. Smoke systems have consume-able batting material, and they need serviced. Please don't confuse maintenance with design. And since you believe the smoke unit is not designed well, please explain what your expertise indicates is in need of improvement? Constructive feedback is always a good posture.
Jon,
It is good of you to post here and I am replying with no small amount of appreciation; you have assisted me in the past (re: Acela). I don't intend to hijack RickM46's thread but since you ask . . .
Speaking as a pure amateur, it's difficult to comment on the current generation of Legacy smoke units without knowing why various design changes were made: plastic components for the smoke unit reservoirs (which in my experience don't hold up to ordinary maintenance disassembly because screw threads are easily damaged), air channels that require the fan motor to be wired the reverse of the norm (no change being made in the impeller design), pads instead of rope wicking, use of thermistors that can easily be put in the wrong position during factory or later assembly are examples that occur to me. All I can say is that up to the changes that were in the Legacy AC-9s smoke units, which I understand involved changing the code used to control their operation, later model Legacy smoke units just do not perform up to expectation and are not easy to maintain.
I have a feeling that most or all of the changes are related but explanation of this has been in short supply.
I will say that when the VLBB was issued, Mike R's video on its operation emphasized that the smoke units use up fluid rapidly. In mine, I have only ever used Lionel premium fluid and been careful to watch for signs that the fluid was getting low - which tends to happen after no more than about 10-12 minutes of continuous operation. Warning people off of overfilling smoke units (as the relevant owner's manuals all do) can itself create the problem of these units really not having an adequate fluid supply - particularly dual chamber units where there is only one filling point.
I for one would like to understand the theory behind the operation of these units.
P.S. I am nostalgic for the VL GE Evo smoke system, which for me always worked exactly as advertised!
I could write a book on smoke systems. Since the introduction of the RCMC system I designed, the smoke system controller and its subsequent tuning was my responsibility, and my nemesis. I spent many long days in China, at the design center, working various smoke bowl and assembly designs with the team. Making a better smoke system has been studied by the brightest folks I know of in the industry, there is not much more, if anything, left to improve. The current designs are pretty good if the smoke unit is built properly and maintained, and it should work nicely for some time.
I really can't comment more as I am not sure what would be confidential in an explanation of the design work to make these smoke systems function. I still have to respect the confidentiality agreements of the company I worked for, and I actually doubt a book would solve the problems 100%.
Still, the forumites are a bright group of folks. And as I stated - any constructive feedback means a lot to the designers.
Jon stop posting on forum! and go traveling without smartphone laptop tablets just you and scenery laughing loudly hope you do get to enjoy retirement
Jon, I appreciate immensely the help you gave me in the re-construction of the new smoke unit for my Big Boy. For me, it was a rush when after help from you and the others in the forum, it worked immensely well - my BB lives! I don't know if you can stay away from the forum; and, selfishly, appreciate your participation.
Now, per direction from the forum, I am looking for a place to hang a document. I have created a Microsoft rich text document from a pedestrian standpoint showing everything I learned about a smoke unit; it might help others when it comes time to maintenance a unit. I would gladly email a copy to someone who can review it and suggest corrections.
SantaFeFan posted:I could write a book on smoke systems.
I'd buy that book Jon, and I don't buy many books.
gunrunnerjohn posted:SantaFeFan posted:I could write a book on smoke systems.
I'd buy that book Jon, and I don't buy many books.
So would I - as long as it’s autographed. 😁
OK, no takers on my Smoke Unit document; so, don't know if I am flooding the forum but here it is:
Lionel Legacy Smoke Units
June 2018
The following information was accumulated from the OGR forum during the repair of a dual stack smoke unit of a 2014 Lionel Big Boy 6-11437. Information came from Jon Z., Mike R, MartyF, GRJ, Sinclair, Hancock52, Falcon70, Romiller49, Davety, and others on the forum.
See OGR thread:
https://ogrforum.ogaugerr.com/...opped-working?page=1
Smoke Unit Components.
Reservoir - metal or black composite plastic, home for the wick, smoke fluid, fan motor secured to the reservoir, fan blades, fan air passage channel to the wick, PCB board secured to the reservoir by micro screws.
See info from MartyF below on metal reservoirs and centering the heating elements.
Stack funnel - allows supply of fluid to the wick; mounts to the PCB board over the heating element; in the case of the Big Boy, the dual stack funnel has 2 separate chambers - one that delivers smoke fluid to the front smoke unit, the other to the rear smoke unit; putting small doses of fluid into a funnel may only wet the funnel especially those funnels that are composed of multiple chambers; the Big Boy funnel with its chambers does not allow the insertion of a long syringe to wet the wick directly with fluid.
Fan motor - mounted to the reservoir; has 2 electrical terminals - one with a white dot; the rotation direction of the motor shaft is determined by which of its 2 terminals you connect the red plus power lead and the black negative ground lead; in Lionel motors, connecting the black lead to the white dot terminal will produce CCW rotation; the fan motor is attached to the reservoir via 2 micro panhead screws - 1.3mm X 2.8mm X .2 thread; the red and black wires connecting the motor to the PCB board are 28-30 gauge and soldered to the board (with my unsteady hands, I found 22 gauge easier to solder); the fan motor can be tested with a 1.5 volt battery if the motor is not connected to the PCB board; 1.5 volts easily runs a good motor.
Fan blade - mounted on top of the fan motor; the fan blade is press fitted onto the fan motor shaft; it should not be glued; it can be removed using needle nose pliers and pulling gently upward; ideally, the motor should spin with the convex part of the blade pushing air through the air channel into the reservoir wick chamber; however, the position of the air channel will determine which direction the fan blade should spin; some say there is no difference whether the concave or convex side of the fan pushes the air.
PCB board - mounts on top of the reservoir via micro panhead screws 1.9mm X 8mm X .4thread; contains a heating element resistor, heat control thermistor, white plug recepticale with 5 pins (sometimes black) for a white 5 position plug (sometimes black) from the RCMC; air intake hole for the fan; smoke exhaust hole over the heating resistor to a funnel that leads to the stack, funnel may be press fitted into the board (Big Boy main stacks), 2 holes for soldering the red and black leads from the fan motor, embedded printed metal circuits connecting the components to the recepticale for the 5 position plug to the RCMC; the recepticale for the 5 position plug from the RCMC has these 5 pins and with the recepticale pins facing upward from left to right are labeled: SENS, COM, FAN, HTR, RAW; when soldering new motor leads to the board, test continuity using the COM and FAN pins.
Heating element resistor - should be soldered perpendicular to the board; must be centered in the reservoir chamber and not touch the sides of the reservoir; its height off the board should be enough to allow it to sleep on the pillow of the wick and not be covered by the wick; be careful not to bend the resistor when installing the resistor into the wick; there should be some resistance from the wick against the resistor when attaching the PCB board to the reservoir; can be cleaned with isopropyl alcohol and a soft tooth brush; can be tested on the board for ~8 ohms; if ohms are higher than ~8 ohms ie. 12 ohms, a cab light error blink will occur and the unit will be disabled by the RCMC; in the process of overheating, some say the burnt resistor may damage the RCMC.
Heat control thermistor - should be soldered perpendicular to the board, parallel to the heating element resistor, its top should be even with the top of the resistor, adjacent to the resistor with a gap from 1.6mm or 2/32 to 3/32 to 4/32 inch between it and the heating element (Big Boy gap is 3/32, some say 4/32 inch is better, mine is set to 3/32); can be tested on the board for ~50k ohms; if ohms are higher than ~50k ohms, a cab light error blink will occur and the unit will be disabled by the RCMC; air between the thermistor and the resistor is a poor conductor of heat when compared to a saturated wick; charred wick and dry wick are also poor conductors of heat to the thermistor.
RCMC board - controls the smoke unit; a 5 position plug comes from the RCMC to a 5 pin recepticale on the smoke unit PCB; at cold startup on a Big Boy and with a medium smoke setting, the amp meter on a ZWL shows a current draw of 6 amps for ~8 seconds, then 4 amps for ~8 seconds, and lastly drops to about 1.7 amps; the RCMC for a Big Boy brings the main stack smoke units online before the rest.
Question: does the RCMC sense when a fan motor is not working??
Fluid - Lionel Premium fluid is recommended for Lionel smoke units; it is thinner than some others; it is not a conductor; it is used in proper amounts (drops) to saturate the wick for smoke production; since it is not a conductor, if a board gets wet with it, you can usually wipe the board dry without damage; too much fluid may also wet the fan motor and damage it.
Fluid dosage - is measured in drops; the Lionel Premium fluid dropper is graduated in .25ml increments; .25ml is about 10 drops; there are some droppers that measure out smaller size drops; Mike R recommends 20 drops per chamber for the Big Boy main stack and 10 drops for whistle and blow down; when installing new wick into a smoke unit, I used 70 drops to saturate that chamber's wick before I screwed down the PCB board - turned the unit up side down to see if any fluid ran out - none did; putting small doses of fluid into a funnel may only wet the funnel especially those funnels that are composed of multiple chambers; after a dose, blow gently thru the stack to break a miniscus; some say to only add fluid when the unit is cold and to let it soak into the wick. some say you have to consider run time and density of the plume to determine when to add fluid; some say to add 20 drops of fluid after 10 minutes of run time.
See more info on dosage:
https://www.youtube.com/watch?v=WRcpFRtA6IY#t=180
https://www.youtube.com/watch?v=1asUWbJtfok
Consider the path of the smoke fluid when you add some: the fluid will have to wet the stack, then funnel, then heat resistor, and then finally the wick; what gets to the wick may be less than the full dose; I have seen excellent smoke after a dose and now know that is because the resistor itself is wet.
String Wick - replacement part number 691SMKP008 (8 inch long string); wick receives smoke fluid thru the stack and funnel; is packed into the reservoir; the string wick is less dense than the original factory block wick and thusly gets hotter, but, must be dense enough (as close to the original factory block wick) and wet enough to accomodate the vaporization of smoke fluid to produce smoke by the heat of the resistor; must not block the air channel in the reservoir from the fan to the wick; must be wet enough and dense enough to provide passage of heat from the resistor to the thermistor so the thermistor can control the temp of the resistor; if the string wick is not packed as dense as the original factory block and is not wet enough, it will melt (per Jon Z.); usually one 8 inch length of string wick is sufficient for a chamber after it has been pulled apart and balled up; I use an 8 inch string wick + 4 inches from another string; use the flat butt end of a micro screwdriver to compress the wick after it is pushed into the reservoir; wick preparation for packing into the reservoir can be seen at:
https://www.youtube.com/watch?v=ZkDlQ5Cwwlk&t=12s.
Charred Wick - charring is the hydrocarbon brown residue on the wick produced by vaporization of the fluid; too little fluid and high temp will cause charred wick; charred wick is not burnt wick; dry wick or too big a gap between the resistor and thermistor will result in charring and overheating and damage to the resistor or thermistor; charred wick between the resistor and thermistor is also an impediment to the sensing function of the thermistor; overheating can also distort the reservoir itself.
Smoke Plume - when the smoke plume begins to get anemic, add fluid; if you smell plastic burning, the wick may be charring.
Dual Chamber Divider - in dual chamber smoke units, the divider separates the chambers; has a cut out passage on the bottom of the divider to allow fluid migration from one chamber to the other.
Micro Screws - black oxide phillips fasteners used in the smoke unit; if not in Lionel parts, stainless steel versions can be found at:
https://www.microfasteners.com...rection=0&page=1
http://www.fastener-express.co...crews-stainless.aspx
https://www.boltdepot.com/Cata...5EAAYASAAEgLkL_D_BwE
however, consider that these screws are stainless and non-magnetic and have phillips heads that are a tad bigger but work in a pinch.
Tools and Parts - a multi meter to check for continuity and ohms, Hakko FX888d soldering station with tip assortment (may require recalibration after testing the soldering iron tip using a Hakko FX100), Hakko FX100 soldering iron tip temperature meter, micro screw drivers, screw driver magnetizer, long soldering tweezers (helps installing the 5 pin plugs into their recpticals and retrieving screws dropped into the chassis), 20g, 22g, 28g, 30g wire, wire nippers, wire strippers, .5mm 60/40 rosin core solder, Quad Hands work station, heat sinks, electrical tape, all the smoke unit parts you can get from the Lionel parts page, micro screws, 8 inch wick, an extra hand to hold your shaky hand steady, long lead time on ordering parts, soldering tutorials on Youtube, unlimited patience; help from the OGR Forum.
Per MartyF (June 17, 2018):
Metal Smoke Reservoirs and Centering the Heating Elements.
Guys, one pointer that you want to keep in mind when working on Lionel or MTH smoke units. Both Lionel and MTH have many smoke units with a metal smoke reserviors where the heaters and wicking reside. Before putting the PCB with the heaters or heater back inside, be sure the heater is centered so it will sit as close as possible in the smoke reservior. Doing this has nothing to do with smoke output. What you do not want is the heater to touch the side of the reservior and ending up doing damage.
Here is what I always do. Take your continuity meter and with one probe hit the heater pad or screw on top of the PCB. Take the other probe and hit the reservior and hope you see no continuity. If you have no continuity, you did the job right and are good to go. If you see continuity, open the unit up again and re position the heaters and repeat the step until you see no continuity.
Today, many of the smoke reserviors are plastic. That makes life easy. Lionel is always a bit easier to do with the single heater. You have all read some of the great info on updating smoke units by GRJ and Alex. Even with modifications to the smoke unit, always make sure the heater does not say hello to the metal reservior.
Rick, you may be lucky. The RCMC is tough. I am a very big fan of the RCMC.
That’s a fine compilation of excellent advice; have printed it for future reference. And wow, I am pleased to be mentioned among some truly distinguished company.😲
Incidentally, I have now got a Hakko soldering iron and the difference between it and the hobby models I have been using is pretty much astonishing.
Hancock52 posted:That’s a fine compilation of excellent advice; have printed it for future reference. And wow, I am pleased to be mentioned among some truly distinguished company.😲
Incidentally, I have now got a Hakko soldering iron and the difference between it and the hobby models I have been using is pretty much astonishing.
Hancock52, yes the Hakko is a good soldering station BUT I also bought the Hakko FG100 tip temperature unit and found that when I set the soldering station to 585F, the tip was only at 450F; you then have to recalibrate the station.
