MTH PROTO 3.0 STEAM UPGRADE AND SMOKE FAILURE

IF this is using the standard steam PS32 upgrade board, the first step would likely be to test the board itself.  If you have had any short to ground of wiring, the smoke fan FET could have been toasted.

Thank you for your input Gunrunnerjohn!! It is greatly appreciated!!

I do not believe that there has been a short to ground of the wiring (I don't see any evidence of this and have been very careful with the wiring, but I guess it remains a possibility).

Is there a process for testing the standard steam PS32 upgrade board?

If the smoke fan FET is toasted, is that a part that might be replaceable without having to replace the entire board?

The process of testing the board would really require the MTH test set, it's treated as a PS/2 board for purposes of testing.  This allows us to exercise all the functions of the board.  The smoke FET is a part that can be replaced, it's a currently available part.

First thing to do, if you haven't already, is measure the smoke motor leads to frame ground.  There should be no continuity to frame ground for any PS2 or PS3 signals except the actual frame ground connection to the board.

Thank you again John another fast  response!!

I really appreciate the detail!!

I will check for no continuity to frame ground from the smoke motor leads tomorrow.

If needed would testing the board be a service that you could provide?

I can certainly test the board and replace the FET if needed.

John,

I just tested the smoke motor leads for continuity to ground (with the tender plugged into the loco and and no power) and found continuity which fades out to an open circuit over a period of 3-4 seconds. After disconnecting the Multimeter probes and waiting 30 sec. +/- this can be repeated 3-4 times before it goes to a continuous open circuit.

I also checked the resistance across the smoke fan motor only and it measured 11.8 ohms.

Does this info. lead you to any other thoughts or suggestions or would the next step be to have you test the board?

Below is a photo of the boards as installed in the tender (just wanted to make sure we are on the same page with the type of boards we are talking about)

That's the PS32 board, that's what is in the standard PS/3 steam upgrade.  If the leads from the smoke fan have continuity right to the smoke fan connection on the PS32 board, and the smoke fan motor runs when tested, the next logical step is to check the PS32 board independently.

One thing about testing the smoke fan motor.  It should not draw more than about 40 milliamps a 5VDC.  If you have a way to test that, that would be worthwhile.  You can get failures like this if the smoke motor is bad and draws too much current, I just replaced a smoke motor for that very issue.

So I rechecked the leads from the smoke fan motor to the board and they both have continuity.

Based on all of this I would like to send you the board for testing and repair (if possible). What is the best way to send this to you (address, etc.) and could you give me an idea of potential costs? Can I send you the boards only to minimize labor,  packaging and shipping costs?

One other quick question though. You mentioned that failures like this can occur if the smoke fan motor is bad and draws more than about 40 milliamps at 5 VDC (I am not able to test the motor right now--need a 5VDC power supply which I can borrow from a friend sometime in the next week or so). When you refer to failures like this (with the information that you have at this point) are you thinking that this is a fan motor issue due to high amp draw or a board or FET failure caused by a high amp draw from the smoke fan motor? Either way, it seems like in addition to having you test the board I need to test the fan motor for amp draw and if it is high replace the motor.

Thank you again for all of your help!!

Did you razor saw cut the solder as shown in the manual?  You can us a dermal with a cut off wheel.

Send me an email to my profile address.

You can also simply send the smoke unit, it's pretty small as well.

PRR, thanks for your input on razor cutting the solder as shown in the manual. Yes, this was done and the unit operated well for approx. 32 hours before failure.

Smoke fans go bad, replace it.  Impeller can get loose and slip but since you said no fan.  If the fet was burned on the PS-32 board it would be visible.  G