Frisco LEGACY Santa FE 4-8-4 #4500 - 2031240 - Whistle Steam Smoke Unit Melted

You might also want to check over the main smoke unit too, as that will also self destruct eventually (I had both of my 3765's smoke units fail back in 2021). The issue is from that diode, which is used as a temperature sensor, is either too high up or too far away from the heating element. You want to have it around 1/16th of an inch away from the heating element.

That smoke funnel you mentioned seems to be the correct part

I had a similar issue with an engine late last year, post link below, check the thermostor spacing, mine was too far from the heat element and caused it to get too hot.  From the pictures it looks like yours is too.

Lionel Legacy 4-6-6T Smoke Unit Help Needed | O Gauge Railroading On Line Forum (ogrforum.com)

@ArtsModelTrains posted:

I had a similar issue with an engine late last year, post link below, check the thermostor spacing, mine was too far from the heat element and caused it to get too hot.  From the pictures it looks like yours is too.

Lionel Legacy 4-6-6T Smoke Unit Help Needed | O Gauge Railroading On Line Forum (ogrforum.com)

Interesting. I'll try to get a better picture of the spacing, but it's definitely more than 1/16th of an inch!

@MichaelB posted:

You might also want to check over the main smoke unit too, as that will also self destruct eventually (I had both of my 3765's smoke units fail back in 2021). The issue is from that diode, which is used as a temperature sensor, is either too high up or too far away from the heating element. You want to have it around 1/16th of an inch away from the heating element.

That smoke funnel you mentioned seems to be the correct part

Thanks for the info on the funnel, I've got one heading my way!

Got the new smoke unit in, replaced the old one, put the sensor (thermistor?) 1/16th of an inch from the heating element, put it back on the test track and....well....

This was, genuinely, maybe four minutes of being powered up. The smoke worked, but then CLEARLY was running too hot. Sure enough, it's not only burned through the wicking but started melting through the side of the smoke unit body!

What am I doing wrong here? This is two in a row with the exact same issue, and I'm not sure what other control I have over the temp of the heating element. I ordered a second spare smoke unit, but I don't want to keep doing the wrong thing over and over.

I'd start by making SURE the smoke unit is controllable by turning off the switch, maybe the board has a problem.  Also, inspect all the wiring between the smoke unit and the board, any short to frame ground or another wire can cause havoc with the power output.

You can swap the whistle smoke and main smoke connectors and see if the overheating follows the board connector or remains with the whistle smoke unit.  I'd only do this AFTER you verify everything else, but it's useful to see if the board has the flaw.

Okay, I can do that. I'll check the switch first, and do another inspection of the wiring, and then swap the front unit to the whistle and see what happens. Thank you for the suggestions!

Is there a better/more qualitative way to test a smoke unit other than putting it all back together and seeing how it produces smoke?

@J.Dooley posted:

Okay, I can do that. I'll check the switch first, and do another inspection of the wiring, and then swap the front unit to the whistle and see what happens. Thank you for the suggestions!

Is there a better/more qualitative way to test a smoke unit other than putting it all back together and seeing how it produces smoke?

I bench test them myself.  All you need is two bench power supplies, one for the heater and one for the fan.  The heater takes 7 to 8 volts for full smoke, and the fan motor is a 5V max DC motor.  I can see the proper smoke operation right on the bench.

You can separately measure the thermistor with a meter.  At room temperature the thermistor measures between 50K to 55K.  Much out of that band and there's probably something wrong with it.  It's a negative coefficient thermistor in that it's resistance goes down the hotter it gets, normal operating range with the smoke resistor hot is in the 4K to 5K range.

I think your first instinct was right. It's not *just* the whistle steam unit, it's both. Even with both dip switches for the smoke units physically in the OFF position, one of the fans immediately goes to 100% power, and the other heating element immediately goes to max power. I tried unplugging both smoke units from the board and making sure everything was seated properly, but that doesn't seem to change anything. I'm assuming this means full board replacement? I just got this from Trainz, so I can open a support case with them to see what they can do.

This stinks, I'd been waiting to get my hands on this engine for a while. I've had a run of bad luck with purchases here lately.

Seems like it's not just a smoke unit issue, it's a firmware issue with this production run of the 4-8-4 Northern

@MichaelB posted:

Seems like it's not just a smoke unit issue, it's a firmware issue with this production run of the 4-8-4 Northern

☹️

Trainz (who has been generally wonderful about standing behind the stuff they've sold me) has asked me to return it so they can repair it. I got the busted Union Pacific  21" "Fox River" Theater Car from them as well, and they are working on getting that one operational as well.

I'd love for everything to show up perfect, but they have been okay to work with on the stuff that isn't.

There is a firmware problem with these engines. A club members engine was affected. His dealer sent the board back to be reprogrammed. Best contact Lionel.
Simply replacing the smoke unit won’t cure it.

Pete

How in the world did these get out into the wild without someone noticing that issue?

Sure smokes great when you blow the whistle. Wish the smaller engines or my 4-12-2 smoked that good. For what it is worth, that whistle is incredible!! Wish I had it on one of my other engines.

@gunrunnerjohn posted:

How in the world did these get out into the wild without someone noticing that issue?

They probably tested the smoke units for like 30 seconds, which is not enough time to notice they're running way too hot and putting out way too much smoke

Wanted to follow-up and close out this post. Send the engine back to Trainz, and they e-mailed me today to tell me it's fixed and headed my way. I asked if they could share the work done with me and they sent this:

The initial inspection is able to validate the loco did not run; further troubleshooting identified the RCMC driver board had failed on the Lionel test fixture. The whistle smoke unit was also missing the brass snorkel sleeve. Allocate and install replacement RCMC driver board, service smoke units, replace batting, allocate and repair snorkel on the whistle unit.

Bench test the loco using Legacy, Bluetooth and Conventional AC control on the test track; the engine runs strong, directional lighting, smoke and whistle steam effect with rail sounds is good.

On one hand, wow. That's a lot to have been wrong. On the other hand, I've been consistently impressed with how Trainz stands behind the used products they sell. I haven't had a LOT of issues, but I've had a couple, and in every case the support has been top notch.

That's impressive Jeramiah, I like that service. In truth, it sounds like the bad RCMC was the primary issue, the missing brass piece is small potatoes and might have been missed by anyone.