First Smoke Unit Repair - QUESTION

Resistor looks bad to me......look to see if any of the windings around the resistor are broken if so its toast.......you can also check for continuity through the end caps of the resistor with a multimeter.....I am quite sure, the heavy hitters on the forum will weigh in on this also. FWIW, i would replace the resistor.....

Hope this helps

 

-Pete

Yeah I didn't even notice but you can see it in the picture if you look close, there is a winding broke and just sticking up in the air.

 

I put the meter on it, and it has no reading at all.

Ok.....thats your biggest clue it is burned out. Get a replacement from Lionel, but be careful installing it.  That is, be careful with the resistor windings....it is easy to break them if you are not careful during the install......buy a few just in case.

Good Luck and you should see a bit of improvement with smoke output.

-Pete

You guys are totally correct, the resistor is broken. This is an 8 ohm resistor part number

691RES8OHM. Doug i have tons of them, if you order it from Lionel you'll have to pay 9.00 dollars for shipping. I can put one in an envelope and mail it to you.

 

Doug this engine is equipped with an AC smoke regulator, the regulator might be the problem too part number 691ACRGE01. It's a 30.00 dollar part. When you replace the resistor, if the smoke unit still doesn't work the Regulator will have to be replaced.

 

Alex

Thanks Alex, for now I swapped out the pcb unit with a TMCC GS2 engine I have, just because it needed tuned up as well. I got some stuff on order from Boxcar Bill. I shoulda known to ask the smoke unit KING....duh!  My bad!

 

Thanks for the input, I'm sure I'll be contacting you direct here soon cuz my Dad has a Legacy Northern that the fan motor went out in. 3 blinking cab lights and no smoke, can't even here the fan running, and it was making a horrible noise right before it went out.

This is why I love the forum-learned a lot just listening to you guys 'talk'!

 

I printed this thread for future reference, thanks boys!

one more postscript on the subject......and Alex please correct me if I am wrong.  If the Ac regulator is dead......the voltage to the resistor is higher....therefore much hotter causing a much higher output of smoke.....inother words if laidoffsick replaces the resistor and he gets smoke like there is no tomorrow, that would mean the ac regulator needs replacing......and the resistor will burn out again, at least that has been my experience. Looking again at his pcb it looks like it is indeed charred and therefore he would also need that ac smoke regulator.  Laidoffsick, please let us know the final diagnosis

good luck,

Pete 

Pete, very good point. Yes i agree with you and i should have mentioned it in my previous post that the smoke PCB does look all charred from a faulty AC regulator. But in the past I've also come across the AC regulator being faulty and the resistor was cold all the time. 

 

On another note, I think when Doug cut the sleeve off the resistor he accidentally ripped the winding around the resistor, which is very easy to do.

 

This type of smoke unit (system) is known for problems with faulty AC regulators

 

 

Thanks,

Alex

 

Thanks, Alex for the explanation.  Bottom line here, i totally agree with your diagnosis that he will need to replace the AC regulator as well as the resistor.

 

-Pete

Thanks Pete,

 

Now we need Doug to keep us posted and see what the outcome is

 

Thanks,

Alex

Well I tried to cut the sleeve off carefully, but it was so burnt it was completely stuck to the resistor. It probably got torn up when it pulled off the sleeve. I figured by looking at the spots around the resistor connections, it was all toast. I ordered a new pcb, a few resistors, and a bunch of batting. So I'll report back what worked and what didn't. I was told the ac regulator was ok because the fan motor works fine.

A little char

Still putting my money on faulty AC Regulator based on pic. 

 

-Pete

Well I took a PCB out of another engine that uses the same smoke unit. I ran it for about 10-15 minutes and it works great. I drilled out the intake hole in the board so it puts out a ton of smoke now, especially with the new batting and no sleeve over the resistor.

If the ac regulator in the engine is bad, how long before it burns up the resistor again? And possibly the pcb?

Is it putting out a substantial amount of smoke...more than it has ever produced before?  If it is I believe the voltage to the smoke resistor is not being regulated and will eventually burn out the resistor as in the pictures you posted of the charred batting and resistor.  Believe me I am a fan of alot of smoke but if the smoke is more than normally seen and the batting gets charred like that it is a sign of a faulty regulator, in my limited experience.  Once again I leave it to the experts such as Alex or Gunrunner John to jump in on this issue.

 

-Pete

It puts out a ton of smoke, yes.... but it's been so long since I've run it with a good smoke unit, I honestly don't know.

I think I'll take the whole smoke unit out of the 3751,  and put it in the 4410 and see if there is a difference. If it puts out a lot LESS smoke, then I'll know that the ac regulator is bad in the 3751. They both use the same smoke unit, but each has their own ac regulator. I'm waiting on parts anyway, so I got time to mess with them.

What should the voltage be at that resistor?

Hey Doug, i have many of the 8 ohm resistors as well as extra PCB boards and fan motors you can have for your and/or your Dad's Northern.   I can drop what you need in the mail or can leave them for you at the club layout if you are coming down to run anytime soon.  

 

You are also welcome to swing by the house and we can out the new parts in here for your and/or your Dad's engine.  I've had to make the same repair on almost any TMCC engine I've owned and have fixed some for Jin Everett's steamers as well.  Although his Legacy Santa Fe Northern was the only engine of his that I wasn't able to fix.  That one has been back into Lionel's repair at least 4 times for smoke unit problems.  

 

Let me know if I can help.  

Doug, Email sent

 

-Pete

The smoke regulator is almost surely bad if you're getting tons of smoke, and that will frequently take out the PCB on the smoke unit as well.  It is great smoke for a short period of time, but it's not worth it in the long run.

 

Agreed, that a bad regulator will give a lot of smoke. Also a 8 ohm resistor will not last ten minutes at track voltage.

 

Bill

I can tell you that the 6 ohm resistor only lasts about 30-45 seconds at track voltage, and it is a spectacular sight!

 

8 ohms at 18 volts is 40 watts, normal operating wattage is in the 4-6 watt range.

Well since I modified the TMCC smoke unit per Mike Reagans video at Lionel, I would say the smoke output is about equal to the new Legacy engines and their smoke output. So I can't honestly say whether the output is normal, or a ton of smoke.

I can say that I ran it in a command environment at full 18 track volts, for a least 10-15 minutes with no issues. Smoke output stayed the same the entire time.

In that case, the regulator probably isn't bad.  You wouldn't have lasted that long, and the smoke volume would have been absurd!

Doug,

Another recent smoke unit thread.  This one has a Northern and BoBot replaced the fan - video link on page 2.  I will be doing my first fan replacement on a K4 as you can see from that thread so I am trying to learn all I can ...

 

https://ogrforum.ogaugerr.com/t...units-and-fan-motors

Hi Greg, I saw that video linked to the forum the same day my Dad's 3759 got the 3 cab light blinks.... perfect timing I guess lol I have watched it several times already, while waiting for the new fan motor to arrive.

 

Most of my TMCC engines are approaching 10 years old, and from the looks of the 1st two I've taken apart, they could have use a smoke unit tune up.

 

If it wasn't for GRJ, I wouldn't even know how to turn my soldering station on  OK, maybe not that bad, but my electronics knowledge is minimal to say the least. 

This is after a 20 minute run, plus the 10-15 minutes of running last night. I assume this looks pretty normal, and its still smoking pretty well.

Safe to assume the AC Regulator is OK?

Doug,

 

 From the looks of this, you're in good shape. Everything seems to be in perfect working order

Nice work buddy!!!!!!!!!

 

Alex

Alex is right, if the smoke regulator was dead, it wouldn't look anything like that!

 

I concur with the above......looks good!

 

-Pete

The triac in the regulator can go bad one of two ways.  Short which means full voltage all the time, or go open.  So a bad regulator doesn't always mean it is shorted.

 

The AC Reg replaces the R4LC triac.

 

The other thing is to reprogram the regulator if smoke output is low.  It has 3 settings.  L, M and H. 

 

Loss of fan is another way to overheat an element.  G

True, but since he had lots of smoke, one can assume the regulator triac wouldn't have been open.   If you have too much smoke, that normally indicates the triac is shorted.  Since the little suckers are $30, I've replaced some of the triacs and returned them to service.

since you had it apart..id wouldve drilled the fan intake hole alittle bigger..gives you more smoke out put..ask alex about that...been doing that to all my smoke units even the mths...and man oh man..big out put...some thought I was using megasteam smoke fluid,but was using mth....cant wait to try out mega steam..ill be clearing out the room big time....

I DID drill out the intake hole

John, I was responding to the poster who stated failed ACREG results in full voltage to the smoke. That statement is not true.  It is one of many possible ways a regulator can fail.  Also Doug unit is smoking a lot, but has not burned up so again a lot of smoke is subjective and doesn't mean an AC REG has failed.

 

I have fixed a lot of engine with just a reprogram of the ACREG and new wick.  It is like an R2LC and it can get confused with a setting also.  The same setting for momentum can effect the ACREG.   G

Just a follow up to my original post with this charred smoke unit.

 

I cleaned it up, drilled out the intake hole, new batting, and new resistor. Smokes like a champ, the PCB is fine. I bought a new one just in case, but this old crusty one works fine for now. I actually put it in the GS2, but the 3751 Northern and the GS2 4410 have equally impressive smoke output now.

 

Back to the bench, several of these older TMCC units to rebuild now.  

I have a number of "brown" PCB smoke units, as long as the fiberglass isn't charred, I don't think about replacing it.

 

Now you're a smoke expert.