David - This morning, just to play it safe, I replaced the XL Decoder with another brand new one.  The first one I had use some on my test stand loco and maybe had made some CV adjustments to it.  I put the loco on my indoor DCC layout for 15 minutes pulling three RhB passenger cars and it ran smoothly........so it was the decoder.   But this loco has been run quite a lot based upon the condition of the wheels.  So I believe eventually it will need new motor blocks due to the normal wear and tear of the axles and their supports in the motor blocks.

Maybe the loco, with 2 motors, is drawing too much current from your DCC booster.

Hello Fellow Hobbyists - I'm doing a DCC conversion on someone's older LGB 20851 Two Motor Block Mallet which has a Phoenix Model 97 DC/DCC Sound Decoder previously installed.  The person knew he striped the idler gear in the rear motor block during a railway crash, and when I removed the motor, the damaged idler gears were obvious. I've done the following: Installed a Massoth XL Power Decoder; installed Massoth DCC Pulsed Smoke Generator; Installed 2 new Idler Gears in each motor block (front motor block also showed some damage too); installed new LGB/Marklin E126050 motors in each motor block which required bending the motor's electrical pins for proper motor block fitment (see photo); replaced two defective carbon brushes in front motor block.

Problem: The loco's motor blocks run smooth when operating on my Piko DCC Central Station test stand or when tested with DC power. But when I test operate the loco on my indoor DCC layout powered by my Massoth Command Station/Massoth Power Supply, the loco doesn't operate smoothly. There's a slight amount of continual surging noticeable at Navigator speed setting 1, 2 , 3 etc. I took the bottom covers off both motor blocks and realigned the wheels/gears to ensure there's properly meshing, no binding, and the loco still doesn't run smoothly. I can't figure out why this loco isn't running smooth as silk like all my other locos. What diagnosis am I missing.......advice please!

kiss is best... congrats

Status Report

I tested the 18 volt LGB smoke unit that arrived today with 13 - 14 volts DCC, my customer's NCE DCC systems layout output, and it smoked like a champ.  So I installed it in the Chloe directly to track power.  Not worrying about regulators or resistors for this install!

Yep, but to achieve their max current, they need a heat sink, so for a couple hundred ma, a 500 ma unit would be good... much over that, just the standard TO-220 1.5 amp unit... then no heat dissipation worries.

If you read the datasheet carefully, you will see the derating as the temperature goes up. These are series regulators, and the "excess voltage" is dissipated as heat. The small adjustable "regulators" are actually adjustable switching power supplies, or a DC to DC inverter. They are more efficient and don't heat up.

So, if the priority is size (which was stated several times) then the larger 1.5 amp regulator is cheap, and smaller than the adjustable switching units.

Greg

When buying LM series regulators, check the spec closely.  I got some that were 1/2 amp, not 1 amp.  And for current under 100ma there is the 100ma version and these are very small.

Yeah, they have been around forever, are cheap, and are fixed voltage... I am not a fan of using an adjustable regulator when not necessary, if they go out of adjustment, you can easily destroy stuff.

Be aware of the heat it can generate, but in your app, it should be minimal.

Greg

Greg - Thanks much for the three pin regulator data and website.....I'll get some of those smaller units.

Tom

Sorry, LDO is "low dropout".... it allows a regulation output voltage closer to the input voltage... helps when the desired output voltage is close to the input voltage.

You can go way smaller with a 3 terminal regulator, see the LM7800 series...

http://www.ti.com/lit/ds/symlink/lm7800.pdf

Greg

I can see that for an HO NCE system, but large scale??????

Greg - My customer says his NCE DCC system puts out 14 volts to the track.......he called his dealer to confirm it.  Sound low to me, but guess he's right.

Tom

Dan Pierce said:

Looking at the pictures, LGB uses the yellow/brown wired smoke unit and the seuthe rating is 11 to 16 volts.  140 ma rating.

LGB 24 volt unit is 2 white wires and the seuthe unit is 16 to 22 volts and 100ma (this should be the hot rating, just a guess).

LGB 5 volt unit with black/white wired smoke unit and the seuthe rating is 4.8 to 6 volts and 260ma.

 

Interesting that the Seuthe colored wires is much the same as to what LGB is using.

Not really. I would bet that LGB buys its smoke generators from Seuthe in bulk.

Greg - The DCC track power is either 18 volts or 22 volts.......I've asked my customer to provide that info to me.  If it's the 18 volts, then I guess I'm destined to use the 5 volt smoke unit instead of the 18 volt unit.......or see how the 24 volt unit performs on 18 volts.

I don't know what an LDO regulator is?

I've seen some pretty small adjustable down voltage regulators too on Amazon and eBay.  The first photo is the smalla regulators I use in locos or rolling stock but it's too large for the Chloe.  The second photo shows an adjustable one I found on eBay that's the size of a quarter: Variable or fixed input 4.5 - 28 volts DC; Constant adjustable output .8 - 20 volts DC; Rated current 2A, 3A max.  Looks like a good fit for the Chloe.

Thoughts (and what's an LDO regulator)?

Thanks

Tom, remember that the regulator ic's (the standard 3 terminal 78xx series) need a few volts "overhead" to regulate, so if you want to regulate at 18 volts, your input needs to be higher..

What DCC track voltage are you designing for? Start there.

You may need to use an LDO regulator.

Greg

Greg - I'm not going to use the Soundtraxx decoder to wire the smoke unit.  Just use DCC 20 volts direct track power.  So, according to Dan Pierce's current draw data, the 18 volt and 24 volt smoke units draw the least current 140ma and 100ma (and heat).  So, I could use a very small regulator at 18 volts.......I saw some very small ones on Amazon today that will likely fit into either the Chloe smoke stack or in the Chloe motor block pin compartment.  Or I could test the 24 volt smoke unit without a regulator.  I'm not looking for perfection, just produce some smoke even if irradic.  Thoughts?  

Looking at the pictures, LGB uses the yellow/brown wired smoke unit and the seuthe rating is 11 to 16 volts.  140 ma rating.

LGB 24 volt unit is 2 white wires and the seuthe unit is 16 to 22 volts and 100ma (this should be the hot rating, just a guess).

LGB 5 volt unit with black/white wired smoke unit and the seuthe rating is 4.8 to 6 volts and 260ma.

Interesting that the Seuthe colored wires is much the same as to what LGB is using.

Greg and David - Thanks for all the suggestions and advice.  As David mentioned, the LGB Chloe, like the LGB Olomana, is very space constrained for installing anything fancy for a smoker.  So I'll experiment around just using direct track power by-passing the decoder which I locate in the rear fuel bunker.  I've installed these Soundtraxx Tsunmani2 4400 decoders into about 6 - 7 of these LGB Olomana/Chloe locos that I've sold to people, or they sent me their loco for the installation......but this is the first time someone really wanted me to add a smoker.  

Right, no "great smoking" solution for the Chloe...

As I finished up my post, IF you can run enough current through the function output AND IF you can "dim" the output AND IF you can get a 24v unit AND IF you add a snubber diode across the element to protect from transients, that MIGHT be your best bet.

That would be my best suggestion for the Chloe...

Greg

If you want "good" smoke, I would go with either a self contained system like the massoth, or a "direct drive" system from the decoder.

Yes, that's a good idea, but not really applicable to the Chloe. The boiler is diminutive, and the stack doesn't have a lot of room neither.