Lionel Legacy Smoke unit takes out Boards

Sorry if this is really amateur, but could it have been the other way around - board failure fries smoke unit? Looks like the impeller melted, which would take some serious heat to do,  and might mean that the resistor got a lot more voltage than it should. As far as I understand it the voltage regulation is on the board and not separate as it was with early Legacy engines. Just askin'.

Darn that's some serious heat to melt that.  Good luck

superwarp1 posted:

Darn that's some serious heat to melt that.  Good luck

No, that's some serious out of focus!

Before you replace the $120 RCMC, consider trying the 691-RCVR-B01 TMCC receiver that sits on top of the RCMC, it's a much cheaper part.  That's where the TMCC function resides.

The fan melting could be the result of the fan motor dying or the impeller binding, I had a similar failure recently.

Not that you shouldn't use a smoke unit (I do seldom leave mine on for long, though I even like the non-perfumed fluid smoke smell), but it seems to me that a lot of posts here concern themselves with smoke issues and/or even disasters. I'm sure most are fine (like most of our "fancy" electronics are fine), but I have real doubts about what amounts to a near-fire in your locomotives, especially the plastic-bodied ones. I don't think that the house is in danger, but these are delicate machines running around with little electric space-heaters blowing full blast under plastic shells, near other electronics. 

This seems ill-advised. It's one of the reasons I don't "smoke" much - and the diesel models now typically smoke far too much, which looks anything but realistic. And it's not black - should be, maybe unless it's an EMD 2-cycle.

We could just imagine that it's smoking.

I fixed a customers LEGACY Y6b recently with the same issue. Super heated and melted all the insides. I had to order a new smoke unit and rubber tube for the whistle smoke. Luckily! it didn't damage the RCMC. The customer tried filling the smoke fluid thru the whistle

Thanks for the heads up. Smoke units on only for the photo shoot. 

gunrunnerjohn posted:

Before you replace the $120 RCMC, consider trying the 691-RCVR-B01 TMCC receiver that sits on top of the RCMC, it's a much cheaper part.  That's where the TMCC function resides.

The fan melting could be the result of the fan motor dying or the impeller binding, I had a similar failure recently.

I understand that.  Does not work in conventional either.  G

I have seen this a few times.  As a rule, the RCMC is a very good board.    I am a big Legacy fan.

I have several legacy units and all of them have smoke unit issues I am currently working on a vision line challenger with both smoke units blown, I have several tmcc and mth proto 2 and 3 units and have no issues with there smoke units.  This has been going on for several years now you think they would make a more reliable smoke unit

Marty Fitzhenry posted:

I have seen this a few times.  As a rule, the RCMC is a very good board.    I am a big Legacy fan.

So Marty on the smoke unit failures you have seen, has the RCMC needed replacing also, or is it still OK?

Rod

Hancock52 posted:

Sorry if this is really amateur, but could it have been the other way around - board failure fries smoke unit? Looks like the impeller melted, which would take some serious heat to do,  and might mean that the resistor got a lot more voltage than it should. As far as I understand it the voltage regulation is on the board and not separate as it was with early Legacy engines. Just askin'.

Sure it could have been.  Either way, the board lets you know you have an issue.  So constant resetting probably not good.  I do think most failures are the motor stops working and then you have no effective cooling on the element.   This board did have U-9 smoke fet and a R60 damaged.  I did notice Lionel parts page shows an optional heat shield.  G

I have found the RCMC holds up.  That is a good board.  FYI when trying to trouble shoot RCMC vs radio receiver.  If the radio board is bad only, pull the board and if the RCMC is good, it will operate normal in conventional mode without the radio receiver plugged in.  If you can not achieve this, go for the RCMC.

gunrunnerjohn posted:

Before you replace the $120 RCMC, consider trying the 691-RCVR-B01 TMCC receiver that sits on top of the RCMC, it's a much cheaper part.  That's where the TMCC function resides.

The fan melting could be the result of the fan motor dying or the impeller binding, I had a similar failure recently.

The Radio (RCVR-B01) would not be related in this failure.   It is just a radio, not a processor.  You can pull it out and everything, sans TMCC ops, will still work.

The RCDR has over current protection on the elements, and also checks for element leads shorts to either chassis or 3Rd rail and shuts down if detected; although this is not foolproof.  I suspect the Feedback Thermistor may have failed, and the Thermistor stops the Boosting of the Element when operating temp is reached.  There is a timer to back up the Thermistor failure, and prevents Boosting run-away. Still at some point it all adds up and things can get pretty hot.  There is an error code flash if the Thermistor fails.

I have gotten two Legacy locomotives, both with Canon motors, that the motor shorted and roasted the drivers on the RCMC.  I was also of the belief that the RCMC had overcurrent protection, is there something about a direct short that it wouldn't deal with?  Both motors measured a fraction of an ohm when I checked them, and they'd shutdown my 5A DC bench supply if I tried to run them from it.  On the one RCMC I was successful at replacing the FET's, the other one had actually cooked the board and I just replaced the board. 

How do you react fast enough to a dead short to save a FET?  Over current protection is one thing, a dead short takes out a FET (a few milli-ohms of ON resistance) before you can even detect it.  Of course you can have elaborate circuitry to protect a FET driver pair as your power supply clearly has; on the other hand, the percentage of failures on the RCMC boards is LT 1%.   There is only so much a design can implement from a practical costing standpoint.  As they say, "can't boil the ocean"....

I don't disagree Jon, just pointing out what I experienced.  I think the RCMC works very well, and those are the only two failures I've run across myself.  I blame the crappy Canon motors more than the RCMC, I was a bit amazed that they were dead shorted in both cases.  One I could have accepted, two was a bit more than coincidence IMO.  I've never seen a Pittman or Mabuchi motor fail in that manner.  I guess I should have pulled them apart to see what happened.

Jon, Any idea what other component can be looked at to restore features, or more likely a main processor fault.  I removed faulty smoke components, still dead.  G

gunrunnerjohn posted:

Before you replace the $120 RCMC, consider trying the 691-RCVR-B01 TMCC receiver that sits on top of the RCMC, it's a much cheaper part.  That's where the TMCC function resides.

The fan melting could be the result of the fan motor dying or the impeller binding, I had a similar failure recently.

Hey me again My Legacy southern crescent's RCVR board just failed. The 4 pin connector broke off of the board. I am needing this part to fix the loco, but where can I find a replacement board alone without having to burn 120 on the main motherboard? 

Thanks as always 

Those are fairly easy to repair, I've had a few of those that I had to replace the pins on.  I have pins that fit that board.  Did all the pins break, or just one or two?  It doesn't make much difference in the repair, just curious how it got broken.   I normally see one or at the most two broken.  Typically, this is done taking it out and bending them slightly to the side, the pins are very brittle.

gunrunnerjohn posted:

Those are fairly easy to repair, I've had a few of those that I had to replace the pins on.  I have pins that fit that board.  Did all the pins break, or just one or two?  It doesn't make much difference in the repair, just curious how it got broken.   I normally see one or at the most two broken.  Typically, this is done taking it out and bending them slightly to the side, the pins are very brittle.

Thanks for the help gunrunnerjohn. The 4 pin socket has completely broken off of its attachment point on the board. I have actually found this board on the lionel parts site under another engine classification. Are all of the 691-RCVR-B01 boards used on both steam and diesel the same? 

I don't know for sure, but I suspect many of them are the same.  All that board does is receive the TMCC signal and process it, that's common for any locomotive I would think. 

If the board isn't damaged, other than the connector, I can put a new one on for you.

gunrunnerjohn posted:

I don't know for sure, but I suspect many of them are the same.  All that board does is receive the TMCC signal and process it, that's common for any locomotive I would think. 

If the board isn't damaged, other than the connector, I can put a new one on for you.

Tried ordering one off of lionel parts, they told me that they are out of stock of the individual 691 board. What is the best way for me to get the board to you for you to replace the pin?

Send me an email to my profile address.

I've got a spare RCMC in my Lionel parts stock.

Jim

Lionel & MTH Service center

Jim, all he needs is the connector soldered back on the TMCC receiver.  In any case, the RCMC is custom programmed for a specific product, so he could only use the TMCC receiver.  That would be kind of expensive for that little board.