Big Boy smoke problem

I found that by removing the plug connector from the motor to the board and putting it back on the two prongs fixed my problem which was similar except that my resistor was heating up OK as there was smoke just lightly drifting out from the stack.


Neil

On further examination, I get a spin from the fan with each chuff so fan is OK. No sign of voltage at the resistor and still no full-time fan action. Wires disappear into a jungle. I guess I'll have to start unbundling them when I have more patience. Any schematics available?

The big Boy uses an "analog" smoke unit.

It gets it's voltage from the AC smoke regulator. (A 1" square board in a heat shrink package) The Smoke regulator board has several output voltage levels controled buy the serial data. It's output is chopped AC and when read by a voltmeter will read from 2.5 to 4 volts AC. The smoke fan motor gets its voltage from the circuit on the smoke unit board. It has the pulses from the chuff switch shaped by a 556 chip on the smoke unit board. The power for the smoke motor circuit is regulated from the output voltage of the AC Smoke regulator board.

So if the fan is running then the board is getting voltage from the AC regulator.

Re-read the voltage at the element using the high setting with the loco running it should be 3.7-4 volts. If it is then the 6-8 ohm elelmnt is bad or clogged.

Carl

Thanks Carl. I will return to the quest for smoke this weekend. I always wondered what was under the mummy wrappings of that board.

Carl, I have some questions. The red wire from the regulator goes to the smoke on-off switch and there is continuity to the board on the smoke unit. The brown wire goes to the motherboard so I'm thinking that's power to the regulator? The black wires go into black wire **** so not sure what is happening there. I seem to have more like 15V at the red wire on the smoke unit. Also, while doing all this, the fan is now on full-time as opposed to only when it chuffs. Does that mean I fried an IC? Still no smoke though I measured voltage at one side of the element. A 326 was never like this...

FlyerRich,

Here is a BB smoke wiring diagram.


It is a bit different than I described in that the BB smoke unit does not use the AC regulators output feed for the motor. Some Legacy locos work this way. The BB does not.

AC comes to the smoke unit separately from the element voltage.
This means that you can have fan voltage with the AC smoke regulator not putting any voltage out. Sounds like you may have popped the fan motor circuit on the smoke unit board?

And you may have a bad AC smoke regulator board as well if you are not seeing any voltage across the element.

The safest way to measure the smoke voltage is remove the smoke output stack from the smoke unit and the element screws are under it. Measure voltage between the element's screws

The part numbers are

691ACRG104 AC REGULATOR (S04 CODE) $30.00

691SSMUK02 PCB / SUPER SMOKE (ANALOG) $28.00 ( PC Board for Smoke unit)

Carl

I remember another problem I had on my BB with no smoke was due to the two ends of the heating element were not secured tight enough on the screw/nut under the board, it was probably a dis or HR connection. I carefully tightened the screw/nut up more and it worked fine

Regards,

Neil

I replaced the PC Board for the Smoke Unit and returned to the state of the fan being energized only by the "chuff" signal. I then replaced the AC smoke regulator board and walla! I now have voluminous billowing clouds of smoke, BUT only at the chuff and not when the engine is at rest. I didn't dream that feature did I? It is supposed to smoke even when not moving?

Well Carl answered me offline and it appears I have been hallucinating. It only smokes when moving. I think I was confusing it with the seuthe units on the Mikados and Pacifics which do smoke all the time. At least my Big Boy is whole again!

So, FlyerRich, are you saying that you goofed and owe Lionel an apology? Regards, Neil

Only if they apologise to me for making me have to fix the other 3 problems with this locomotive. I'm just glad that it works as intended again. It's a pretty awesome machine. I want a Challenger too but can't quite reconcile the expense in my head for something that may or may not be trouble-free. We'll see....

I am in a more difficult position than you in that I am the other side of the pond which makes the challenges more difficult. I have pulled my BB down at least three times to resolve issues and my Challenger just once so far. I don't have the luxury of you guys to send it back to Lionel for a fix, the cost is prohibitive. Fortunately I am fairly competent to understand the well enough to keep them as they should, I'm not as well learned as Carl is but I have corresponded with Carl and Mike at Lionel for clarification. In reality it isn't much different to repairing old Flyer stuff, we just need to take a new approach to fixing them and get on with it. Regards, Neil

Seem to have developed a similar problem with my BB. After a couple of hours run time the railsounds chuff and puffing smoke ( I assume the fan) became intermittant and then ceased. It still smokes but does not appear to be puffed by the fan. Bell, whistle and brake sounds all still work OK. Removed the boiler (yikes!) and no loose connections or chaffed wires. Have no idea as to which board is what. Any ideas?

  Also noticed that my tender was leaning to one side and lifted a rear wheel off the track when pressure was applied to level the tender although it always ran on track OK. After disassembly there was a single fiber washer installed on one of the four screws fastening the long truck to the chassis floor. Since I saw no reason for the washer, reassembled the tender and now sits perfectly level and runs fine.

  Also corrected a drooping rear coupler by tightening BOTH loose screws.

  Any tips on the chuff problem appreciated as I'd like to avoid sending the the BB out for repairs.

 

Rich

Sounds like the "cherry switch" this is a switch located on the top of the front set of drivers, between the frame and the wheels. If you pivot the front driver set and look in between on the top of the gearbox you will see the wires going to it.On the bottom of the switch is an arm that rides on a cam on one of the drive axles. If this arm goes out of adjustment and doesn't make good contact with the cam to fully open and close the "cherry switch" the chuff and smoke are lost they are controlled by this switch.Most folks have fixed this problem by adjusting the switch, if this doesn't work, the switch will probably need to be replaced.

I got this from a forum member (can't remember who) some time ago and it helped me with this particular problem. You don't have to remove the boiler:

 

"The switch is located in the rear motor frame and the axle that has the cam is the second one in from the rear trailing truck, the same axle that the main con-rod is connected to.

I made an error in that you don't use the box spanner provided to remove the con-rods, you need a small allen key, I used the box spanner to remove the nut screws from the rear wheels to spring the cam wheel assembly out.

All this can be done with the engine upside down, boiler still on, but be careful with the front bell as it tends to rest on it and if in the wrong position it will spring itself out. I placed it on a thick 'throw' that my wife uses for covering furniture, when she wasn't looking.

There are three large screws that are in line on the keeper plate, you can remove these first and there are two much smaller screws opposite each other, 'tip', don't remove them, just slacken them off about a 1/4" or less, just enough so the keeper plate comes off OK, if you take them out you will need a bit of patience to get them back in again.

I made up a little tool with a notch in the side so that I could adjust the arm on the switch and 'set' it in the new position. I can't remember if I set it lower or higher now, but adjusting it a little bit at a time and then listening for the switch to click every quarter will tell you if you have done it. In all it took me about an hour from beginning to end.

I came to the conclusion that the lobes on the cam are not equal in size and one doesn't operate the switch correctly."

 

I would also check that the switch is firmly mounted. If the screws are loose it will also create problems.

That was me!!! glad it worked OK for you FR. Regards, Neil

Looked at the rear power unit, 3rd axle and some of the wires going to the cam switch were really long and twisted between the chassis and the truck, even almost rubbing the drive wheels. When I moved them back up into the chassis, lo and behold a black wire was not connected. The switch has a capacitor wired across it with a gray and a black on one side and I assume the loose black on the other. Can anyone confirm thats where it should be resoldered?

 

thanks, Rich

I thought so but wasn't sure. It definitely helped with the mystery. Thanks for that!

The switch has a capacitor wired across it with a gray and a black on one side and I assume the loose black on the other. Can anyone confirm thats where it should be resoldered? 

The diagram Carl provided shows black wires at the switch. As soon as I can I will try to confirm for you.

Also, which side of the board does the antenna connect to, engineer or fireman side? Should've marked it when I disconnected it.

 

thanks, Rich

I can't really see the connections too well with these old eyes. I would say that if you have a disconnected wire that seems to fit onto that switch then that's it. I do see a black wire extending all the way to the rear trailing truck as well. The antenna connector goes into the socket that you won't have to twist it 180 degrres to mate it up.