Module Over Temperature

[Espeelark]

In an earlier thread, I posted about my first / one-and-only LM-3s install in an Athearn GP40X. Since then I had a shorting issue that I think has been corrected by adjusting how the (headlight) wires got tucked up into the shell. To test that I ran the loco for and extended period of time to affirm that fix. All seems OK. I was checking the loco parameters in the process (voltage, current, temp) and noticed the module was approaching "warm". So, I juiced it a bit more to encourage it to get into the "warm" zone to see what would happen. I soon got a "module over temperature" notice. Shortly there-after the loco just went dead - sound, lights and all. Stayed that way for a couple/few minutes and then I cycled the power to the track and it came back to life. I checked the module temp and it was back down in the "good" range.
Question - is it supposed to do that? Is that a built in self-protection feature for the module to shut it down before it fries? Or, did my loco just shut down coincidentally for some other unrelated reason?
Trying to understand if the LM-3S module is protecting itself here, or, if perhaps I didn't really fix my earlier shorting issue.

[Alan]

Question - is it supposed to do that? Is that a built in self-protection feature for the module to shut it down before it fries?

Yes. Built in protection feature.

[Espeelark]

So I have only one LM-3S RailPro module equipped loco at this point. I've got a couple more modules on order which will help me compare/contrast in the future, but the LM-3S module I installed in my Athearn "DCC Ready" GP40X appears to run warm. I was running it roundy-round today for ~ 10 minutes, no freight cars in tow, flat and level. Watching it on the HC-2B, it again started creeping approaching the "warm" threshold. The loco shell was in the area of the LM-3S module was warm to the touch as well. The throttle was at ~70% and current (power) was somewhere around the 50% range.
What, if anything, does this suggest to the more experienced/long-term users?

As an aside, and I'm not sure it's directly related, intermittent shorts started occurring as the module approached "warm". The loco would stop, sound & lights would go off, then come back on and start moving again. When this started occurring, it initially seemed to happen in the same locations on the layout, but as it got warmer, it started happening more frequently anywhere on the layout and then would only move forward a fraction of an inch before stopping again. It got to the point that I could tap the shell and it would momentarily come back alive only to instantaneously die again. I'm calling it a short because that's what it seems like. But then again, perhaps the LM-3S module is at issue? The HC-2B didn't ever list any faults when the  loco would die/short. Also, the PWR-56 power supply never reports a fault suggesting the output is shorted.

Any help/suggestions would be appreciatted!

[KiloWhiskey]

Maybe an intermittent solder joint acting up with the heat. My advice is to swap out the module when the others arrive and test again. Also call (not email) Ring and ask for advice as well. And soon you should also have smarter people than I replying to this.

Let us know what you find...

Kevin

[nodcc4me]

The fact that you can affect the problem by tapping the locomotive would seem to indicate that something is shorting out. Possibly two wires touching each other or a ground point. Check the wire connections to the motor and make sure none of the harness connector pins are bent. Nothing inside the module moves, so tapping wouldn't have an effect on it.

[BruceRogers]

I've had module over temp issues as well. If you're using the older pre LED lighted locomotives the problem is caused by the incandescent bulbs. If you run you locomotives for long periods you'll see it rise. I you turn the lights off the temp will drop if you want to do an easy test. I've changed most of my lights out for LEDs. Never had a problem since.

[Espeelark]

Thanks Bruce - yes, this Athearn GP40X has stock incandescent light bulbs and has qty -8- when you take into account the SP light package. I will give that a whirl and see what that does (after I get to the bottom of my intermittent shorting issue).

As an aside, what kind of LED's do you use/install? Make, model color?

Thanks!

[Alan]

If you are up to it you could use a simple transistor circuit on the LM output pin. That would let you run as many incandescent bulbs as the transistor can handle while the LM happily sees little load.

[EDIT] My bad. Accidentally posted active high driver diagram. New diagram is active low and would actually work.

[BruceRogers]

These are the common warm white LEDs I use. Purchased off eBay.

T0603WM 20pcs Pre-soldered micro litz wired leads Warm White SMD Led 0603

T0402WM 20pcs Pre-soldered micro litz wired leads Warm White SMD Led 0402