Issue with smoke unit (but maybe something else?)

Still stumped...any thoughts on what I should check?  It is almost like the old whistle voltages with a high initial and lower running where the fan motor is getting the "kick start" but the running voltage fails to be there...

Thanks again, S/F Mike

Is the element getting hot just no fan?  If so check the regulator for making 5V for the motor.  If element not hot either, then maybe the R2LC or R4LC depending on model, or an ACREG failure.  What is model #?  G

Thanks so much for the reply and Yes, the resistor is getting  hot.  It does appear to me that the noise maybe coming from the AC regulator and is more pronounced if the smoke unit is "on".  Is the 5V regulator the heat-shrinked pkg by the smoke unit?  I assume the AC reg is the pkg by the volume pot.

So would it be an issue with the reg or some other problem causing the Reg to have an issue?

Thanks as always for your insights!

S/F Mike

Sorry, forgot to include the model in the text (stuck it on the photo); this is a Lionel 28240 LionMaster SD80MAC.

S/F Mike

The AC regulator is the module next to the motor that's still cable-tied to the locomotive.  Have you reprogrammed the locomotive?

If the heater is getting hot, I'd check the regulator circuit that George suggested, that's the top suspect.

Thanks John for the reply,

I've not tested the regulator circuit that before, can you suggest a test I might try?

When it did not work at first I did re-program it with engine function code 8 and it acted the same as before.  

Is the reg circuit the shrink wrapped pkg by the smoke unit?  I don't see that on the Lionel parts diagram or call-out..

Thanks again, Mike

OK, let me guess the regulator circuit it on the board on the smoke unit... I plugged in a different smoke unit and it worked fine so I now assume (with your help!) that I need to replace smoke unit cover board.  

I'm still wondering what that pkg is by the smoke unit...

Thanks again George & John!

S/F Mike

The package by the smoke unit is a different regulator circuit that's not shown on the parts breakdown.  The smoke regulator is at the rear, and from your diagnosis, it's fine.

You don't need to replace the whole smoke unit, there are a couple parts that are the likely failure points, and they very cheap.  The top suspect is the 78L05 regulator shown below.  Next in line is the blue cap next to it.  Finally, there is a surface mounted diode next to those components.  One or more of those components should solve the fan issue.  I'd start with the regulator, they've been the most troublesome for me.

Thanks again John and looking for a part number on the board I think I found the culprit..the non-polar Cap in the corner, it was loose and the base has a bulge...looks like it went bad and pulled itself from the board.

I'm not an electronics expert...is there a suitable substitute for the SBP 50V 1 uF non-polarized or do I need to look for that exact part?

Thanks as always!

S/F Mike 

This is fun right?  I sent you the above question and looked across the table at another waiting project and there are two of the caps sitting on an AC motor brush plate..."borrow" one for the smoke unit and now the fan is running great...but the resistor is now cold....did double check the resistor and it is a good 9 ohms...thoughts?

HNY!  Mike

Thanks again & Happy New Year !!!

Guess maybe I was not patient enough for the element to warm up ... gave it some boosting and all is working great now!

Thanks again for the assist John & George!!  I can always count on this group for help when I need it!

Semper Fi, Mike

Remember, the "boost" doesn't work the same way with a voltage regulator.

AUX1, AUX2, 9 H, then AUX2 again to save the setting.  This sets the smoke volume to high.

The L,M,H, buttons are the momentum buttons under the cover, they also select smoke volume as in the command sequence above.  Substitute the M or L buttons for lower smoke volumes.

John, Got you fixed up and glad it was just the cap.  G

The lighting & pic don't do the smoke justice but it is working great now.  Thanks again!

S/F Mike