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I have a thing for the very early PS2 steam locos with the die cast metal coal loads. I thought I struck it rich with a Rail King NYC Mohawk buy on eBay. The condition was pristine with almost no run time. The 9v battery was dead so I got a BCR from J&W Electronics. The head lamp was bad. No big deal, I can replace that. But man oh man did this thing smoke! Was shooting a video to share with a friend when fire started shooting out of the stack. Very impressive but not good. Long story short there is a lengthy thread from way back that discusses this issue. I measured a full 24 vdc to the smoke unit and the head lamp. The parallel 16 ohm resistors make 8 ohms so 24x24/8 = 72 watts when it should be less than 10. And yes, smoke fluid is an oil and if you get it hot enough the vapor will ignite. I tried a factory reset, no luck. My best guess is that the prior owner decided to shorten the python cable by pulling most of it inside the tender and maybe damaged a wire.

I found an LED that can handle the 24 volts so I now have a head lamp. My plan for the smoke unit is to get a 16 ohm power resistor, add that in series with the smoke unit and sink it to the chassis. If the 24 volts holds I'll get 1 amp through the smoke unit resistors and 8 watts. Does this sound sensible or am I about to do something dumb?


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Thanks John! Also thanks for all your help with my failed TIU via direct email. Turns out that most likely the two diodes that died in the TIU were the result of a careless accessory wiring mistake on my part. I created an intermittent track short that eventually became a full short. After I corrected the short. I reconnected the TIU with the shorted diodes disconnected and everything is back to normal. I purchased some replacement diodes to replace the ones that shorted.

The smoke unit issue is most likely the smoke FET on the board.  That's what happens when that FET shorts.  It's likely that replacing Q311, the IRLL2705 you will return to normal smoke operation.

I was thinking that, but the other statement is what makes me question- the headlight also seeing insane voltage.

Both heater and headlight are off the same "PV" derived most times in steam across the motor wires through the diodes at the connect to the engine.

I could be wrong, but again that combined 2 things, both known to be off PV- derived in the same way from diodes across the motor wires- this just seems like a short to frame somewhere possibly and deeper failure IMO.

Hi I would be glad to help you send me an email of boards you need or need repaired! ps 2 5-volt boards are over 20 years old, better to get ps2 3-volt board if you can find one or as someone has, I doubt you'll one. the best option is a PS 3/2 board upgrade and change speaker to 4 ohm , super cap is built into ps3/2 board. Alan

Last edited by Alan Mancus

I still do repairs:-).  Bulbs can go, or fet failure.  But if you have a smoke element return wire pinched to chassis, the PV has direct source to chassis ground.  PV on a 18+V track is around 22+ V DC.  So you have about 3 amps through elements vice approximate .5amps.  Or the board does have issues and full voltage being applied to lights and smoke.  How about Cab light and firebox are they ok or out too.  G

Hi GGG! Hope you are well. You don't remember but you did 2 or 3 repairs for me in the past. If you have a little plastic green dumpster with wheels on it on your desk somewhere that was me. Actually, there is no fire box on this model. Or reverse light. Other than the head lamp and smoke unit everything works perfectly. To Mike's point above, I'm not inclined to spend more on a new board than I paid for the engine. That said, dumb or not I may try adding the 16 ohm power resistor in series with the smoke unit just to see what happens unless I'm courting further damage. If I'm getting a reliable 24 volts then the power resistor (the gold kind with the fins) should work.

But there definitely is something I may need your help with. I have a Premier steam engine. The pride of my fleet. It was running at about 18 smph when the dumb screw that attaches the drawbar to the engine fell out. Suddenly the entire consist load was on the engine side wires connected to the drawbar. I'm sure there was a good yank, and then she stopped dead. I've tried EVERYTHING but it's not firing up or recognized on the track by DCS. I'm guessing the sudden pull either broke a wire connection in the connector or in the engine. If that is the case, there may be nothing I can do unless there is something obvious to look for IF I take the engine apart. I'm reluctant to do that with a Premier engine.

Do I contact you via email if I want to arrange for a repair?

Thanks and regards, S

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