MTH 30-1170-1 Smoke Fan Not Working

Springs for fan may not be making good contact. G

@GGG posted:

Springs for fan may not be making good contact. G

I thought that but everything is tight as far as I can tell. The plugs are seated all the way. I'll look very close at the pins between the end of the springs and the plug since maybe they could not be connected even though it feels like it.

Power fan via battery through those springs.  Will tell you if the wires are good and connection fine.  At that point if you have voltage on the pad, it has to be spring contact. I typically raise them with some thick tape under pad, or nylon washers.  G

@GGG posted:

Power fan via battery through those springs.  Will tell you if the wires are good and connection fine.  At that point if you have voltage on the pad, it has to be spring contact. I typically raise them with some thick tape under pad, or nylon washers.  G

Will do.

I'd clean this up as well, that's a short circuit and a cooked heater FET just waiting to happen!  Also, that wire is barely handing on to the connection anyway, it's very likely it could come loose.  If it shorts to the frame, bad things usually follow!

@gunrunnerjohn posted:

I'd clean this up as well, that's a short circuit and a cooked heater FET just waiting to happen!  Also, that wire is barely handing on to the connection anyway, it's very likely it could come loose.  If it shorts to the frame, bad things usually follow!

I'll fix that wire while I'm in there.

@gunrunnerjohn posted:

I'd clean this up as well, that's a short circuit and a cooked heater FET just waiting to happen!  Also, that wire is barely handing on to the connection anyway, it's very likely it could come loose.  If it shorts to the frame, bad things usually follow!

I'd agree. Also check the solder job on the fan motor. That looks a little subject as well. If you have a multi meter I'd check for continuity from the fan motor terminals to the spring contacts as well. If the springs aren't making good contact with the pad I've had luck removing the springs and stretching them a little bit to lengthen them for better contact.

@Lou1985 posted:

I'd agree. Also check the solder job on the fan motor. That looks a little subject as well. If you have a multi meter I'd check for continuity from the fan motor terminals to the spring contacts as well. If the springs aren't making good contact with the pad I've had luck removing the springs and stretching them a little bit to lengthen them for better contact.

I check the fan leads, there's continuity with the springs.

@Trainlover9943 posted:

I check the fan leads, there's continuity with the springs.

It's probably spring contact with the pad like George mentioned above. If the wires connected to the pad have continuity then you just have to make sure the springs contact the pad and you should be good.

@Lou1985 posted:

It's probably spring contact with the pad like George mentioned above. If the wires connected to the pad have continuity then you just have to make sure the springs contact the pad and you should be good.

I'll check it out and report back.

Well, I checked and tried everything and still nothing. Works fine with a 9v on the springs. I did fix that heater wire. Attached is a picture of the spring board itself and you can see I did lengthen the springs.

If you have a meter, did you check if there is any voltage going to the motor?  You may have a damaged transistor which drives the fan motor.

@stan2004 posted:

If you have a meter, did you check if there is any voltage going to the motor?  You may have a damaged transistor which drives the fan motor.

How can I check since the spring pads need to make contact with the little board to get power. I have a meter.

You can check continuity between the pad and the wires leading to it at the harness connector.

@Lou1985 posted:

You can check continuity between the pad and the wires leading to it at the harness connector.

True. I'll check and see.

Is the only connection to the boiler those pads for the smoke unit? If continuity to the pads checks out check for voltage at the pads with the locomotive powered up and smoke on.

@Lou1985 posted:

Is the only connection to the boiler those pads for the smoke unit? If continuity to the pads checks out check for voltage at the pads with the locomotive powered up and smoke on.

The smoke fan and heater are on one pad, the headlight is on the other. Left springs are the fan, middle is the heater, right is the headlight.

Like suggested above if continuity checks out see if there is voltage at the pad with the smoke on.

@Trainlover9943 posted:

How can I check since the spring pads need to make contact with the little board to get power. I have a meter.

By "voltage going to the motor" I mean from the PS electronics.  So this would be the voltage between whichever 2 pads in above photo mate to the 2 springs going to the motor terminals.  As you know as long as smoke is turned on the fan runs even when the engine is idle (not moving). 

And since you have some spare known-good motors...and know which end of the soldering iron to hold...you could also tack on a couple wires to a spare motor and touch them to the 2 fan motor pads.  If you get no joy, then my guess is a damaged fan transistor.  These transistors are inexpensive but replacement requires soldering finesse and the eyesight of a teenager.

Still nothing. Voltage is getting to the pads. I guess. I tried a spare motor on the middle pad, it did buzz, then I took it off. I tried on the pad closest to the front too but when I touched it, the engine shut off and started up in conventional. So, who knows what going on with this.

@Trainlover9943 posted:

Still nothing. Voltage is getting to the pads. I guess. I tried a spare motor on the middle pad, it did buzz, then I took it off. I tried on the pad closest to the front too but when I touched it, the engine shut off and started up in conventional. So, who knows what going on with this.

Not sure I understand what you mean by middle pad (singular) or pad (singular) closest to front?

My best guess based on your measurements and your previous photos is as above.

The fan motor voltage is on the two pads as shown.  That is, the green and gray wires going to these two pads come from the PS electronics.  And then after going thru the two springs, one sees green and gray wire colors going to the fan motor.

Likewise, I believe the heater voltage is on the two pads as shown.  Again, the purple and brown wires going to these two pads come from the PS electronics.  And then after going thru the two springs, one sees purple and brown wire colors going to the heater elements.

Then by process of elimination, the two middle pads must be the headlight voltage.

I can't explain why the engine shutdown and restarted if you carefully touched the two wires from a spare motor to the two right pads (FAN+ and FAN-).  3.8V DC is a "good" voltage for the fan motor.  Perhaps try it again with extra attention to a potential stray strands of wire or whatever.  That is, if attaching a fan motor to these two pads causes such a reaction, how can it work when you mate the spring connectors which also attaches a fan motor to these two pads?!

@stan2004 posted:

Not sure I understand what you mean by middle pad (singular) or pad (singular) closest to front?

My best guess based on your measurements and your previous photos is as above.

The fan motor voltage is on the two pads as shown.  That is, the green and gray wires going to these two pads come from the PS electronics.  And then after going thru the two springs, one sees green and gray wire colors going to the fan motor.

Likewise, I believe the heater voltage is on the two pads as shown.  Again, the purple and brown wires going to these two pads come from the PS electronics.  And then after going thru the two springs, one sees purple and brown wire colors going to the heater elements.

Then by process of elimination, the two middle pads must be the headlight voltage.

I can't explain why the engine shutdown and restarted if you carefully touched the two wires from a spare motor to the two right pads (FAN+ and FAN-).  3.8V DC is a "good" voltage for the fan motor.  Perhaps try it again with extra attention to a potential stray strands of wire or whatever.  That is, if attaching a fan motor to these two pads causes such a reaction, how can it work when you mate the spring connectors which also attaches a fan motor to these two pads?!

I agree, the ones on the right are definitely for the smoke unit. I'm not sure what to do at this point. With your idea in mind I'll try the fan again and see if I can get it to spin.

Well Stan, you were right. That pad that you labeled as fan + and - is the fan and I tried my spare motor and it worked. So the output is functional.

Well, I think I found my issue. I must have put the spring terminals on wrong. The instructions have the smoke unit toward the front and the headlight on the back. I had it reversed.

Then stating the obvious, since you previously confirmed continuity from the two springs to the motor, somehow one or both springs are not contacting their mating pads.  I'd rather have that problem than not having fan voltage on the pads!

Ah ha!  If I understand what you're saying the two fan motor springs were contacting the pads on the left which go nowhere.  I wonder if anyone picked up on the "scratch" marks circled in red!

Well, it smoke but now the headlight is acting up. Almost like it has rule 17 lighting. Not good.

See if the headlight flickers when you turn the smoke off on the remote.  If that stops it, you probably have a poor connection somewhere.  There was a rather lengthy fix for a similar issue for premier steam with 5V boards that had a mux board.  Your video looks a lot like that problem.

@gunrunnerjohn posted:

See if the headlight flickers when you turn the smoke off on the remote.  If that stops it, you probably have a poor connection somewhere.  There was a rather lengthy fix for a similar issue for premier steam with 5V boards that had a mux board.  Your video looks a lot like that problem.

I'll check, it never did this before though.

Looks like I got it. I had to move the plugs around though. The headlight was turning on and off with the smoke. Now it's worked the way it should. Thanks everyone!

Way to go, Matt. Aint this forum great?

@John H posted:

Way to go, Matt. Aint this forum great?

It sure is!