Hey all,

I have installed a used LM-3S in my old Athearn blue box GP-35 diesel. I have all the light functions working including a PBM-2.

The one thing I cannot seem to get working is the speaker. I have a single, wired speaker that will NOT work when plugged into pins 1 and 2 of the 6-pin connection on the LM-3S. I have another GP-35 with the SAME speaker plugged into another LM-3S module that functions beautifully.

Has anyone ever had specific pins on an LM-3S fail? Doesn't sound right. I tried another speaker and it still didn't work.

I changed up the sound files on the buttons on the HC-3 for the locomotive and I can't get it to play any sounds.

I did have to flash new firmware for this module and the new version was confirmed in the controller.

Is there some kind of reset I need to do to get this to work? I don't see any physical damage to the pins and I have confirmed the speaker works with another module.

Any ideas?

Thank you,

Rob

yeah, run it at 9 volts and check the current draw, then run it briefly at 12v and note the current.

no, if run OVER 9v the solder may melt... assume 12v (typical HO DC voltage) now you are running the motor 50% in excess of design voltage, remember motors are usually nonlinear at the extremes...

I would guess the copper "springs" (look at the pictures) to the axles have too much resistance and create heat....

Interesting, it's stated that running over 9v will melt the solder on the pickup springs in the truck.

The implication is the current will go up enough the melt the solder, so, right off the bat, not a great design.

I'd put a diode chain in series with the motor lead to reduce the voltage the motor sees... that should keep the current levels below the "melt solder" levels.

(can you say poor design by Atlas?)

Greg

Hey Tim,

IIRC, the instructions did mention something about sharing the load with the loco. I'll have to re-read them. I'll also see about cracking it open and see the wiring. Gotta do it anyways to access the 8 pin plug.

Stay tuned.