Do I need a new smoke unit board for Lionel #773 hudson from 31739 Lionel Postwar Celebration Series set?

What kind of "juice" are you giving the fan motor?  It run on 5VDC, don't use AC or anything more than 5VDC.

I have this set, I bought it brand new in 2006, I believe you have a standard 27 ohm smoke unit. There are no parts listed for this locomotive. Try doing a search on the Lionel web site for the 6-38010 JLC Clinchfield Challenger. You should be able to get smoke unit parts to repair yours. You can buy the smoke unit reservoir with the motor and fan, the 27 ohm resistor etc. The board itself may be a little different, depending on where the hole is drilled for the smoke funnel. But you should be able to make something work. In Google type in Lionel 6-38010, go to the bottom of the screen and click on replacement parts. Put the number 6-38010 in the search.

If it has fan-driven smoke, your loco must have been upgraded at some point.  From the factory, those PWC Hudsons had TMCC command control and mechanical puffing smoke like 6-18058 and many others.

I can't advise you on the interplay amongst the electronics.  But posting some photos would help the real experts on this board see what you have and give you some tips about where to start.

Sorry, I am new at photo posting.  Hopefully four pics are better than none!

By reprogramming the loco, I did get the unit to work, sort of.  However, it has been 'smoke-leaky'

and sometimes it does not respond to the smoke command.  So, it would be good to be able to

locate a unit like the one above (from my loco).

Thanks, all, for your helpfulness!   

PAsteve

Before we go off the deep end and start assuming you need a replacement board- which is probably NOT the reason, let's make sure we understand NORMAL operation of this smoke unit and expectations.

The smoke unit is turned on by the R2LC smoke TRIAC feature output. This controls and powers the heating element and also, enables the fan function- but more on that later. Again, heater is not even controlled by the PCB smoke unit. It's simply a connector to the heater.

As such, since the R2LC is controlling this- there are feature codes for TMCC engine like this, and that feature code setting, when setting the address of the engine determines the output function of the smoke TRIAC. So first things first- ensure you reset the feature code in the engine. This is covered in the manual. manual link https://www.lionelsupport.com/...ents/73-1739-250.pdf

Page 20 of the manual

Part2- setting expectations!!!

This is a Lionel semi smart smoke unit- or as I call them dumb units. This is because they do NOT have idle smoke fan operation. The smoke fan ONLY spins and "puff"s when the engine is moving and the board is setting chuff pulses from the chuff switch. Again, the fan sits there doing nothing unless the engine is moving and the chuff switch is sending pulses and the fan only pulses matching the chuff sound- but defaults to off if no chuff is received.

Bottom line- I highly suspect this may be as simple as using the right feature code.

I will say- this engine is a candidate for the super chuffer- highly recommended modification to control the fan and get idle smoke.

@PAsteve posted:

Sorry, I am new at photo posting.  Hopefully four pics are better than none!

By reprogramming the loco, I did get the unit to work, sort of.  However, it has been 'smoke-leaky'

and sometimes it does not respond to the smoke command.  So, it would be good to be able to

locate a unit like the one above (from my loco).

Thanks, all, for your helpfulness!   

PAsteve

Sorry, I may have been typing while you replied.

Again, the only thing that smoke PCB does is control the fan- and by design- that board had limitations in how the fan operates- only when moving and getting chuff pulses.

I would not spend the effort and time to replace with the exact same board. First off, they are not available and even if you comb the earth trying to find one- I doubt you will find one. The super chuffer is about the same price as you would pay for that board. It is basically a substitute fan controller.

Also- this is experience talking- those tiny N20 sized fan motors often fail with a weak or dead armature segment and may not "self start" when power is applied- and given the pulsing nature of the semi-smart smoke unit operation- it's possible the fan motor fails to start because it randomly stopped on a dead or weaker segment of the armature. I always use replacement smoke fan motors (yes, even in big L product) from MTH parts and sales as I have found them to be so much more reliable and long lasting of a smoke fan motor. They are the exact same size and rating, just for whatever reason- a better motor.

The 773 Locomotive from the Lionel #13150 Super O Steam Freight Set #6-31739 has Command Control, with a fan driven 27 ohm smoke unit. The 6-18058 Century Club 773 Locomotive has Command Control and mechanical puffing smoke. I have both Locomotives that I bought brand new. I have always wanted to put a Super Chuffer in my 773 Locomotive from the Super O set, so it has synchronized smoke. But mine is always just a parked line on my Christmas layout, with the operating Horse Coral, Milk Car, Chicken car etc.  The smoke unit in your 773 Locomotive does not belong in it.