I have an RS-11 with a DCDS FM1 board that has pulsing motors. I noticed that if I slowly accelerate that this isn't an issue which has me wondering if the capacitors are bad. Has anyone tried this fix?
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I have to say, I've never had the capacitors go bad on the DCDS. Truthfully, most of the time the DCDS just fails or it works. Have you disconnected the power to the motors and run them on a DC supply to see if this is a motor or mechanical issue?
The motors seem to run really well at all speeds from min to max throttle but if there is a speed jump they pulse. See attached video.
Can I test them with a 9V battery? I unfortunately don't have a bench DC power supply.
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Videos (1)
Check the end play on the motor armature that has the sensor attached. If that is excessive, you'll get exactly that behavior. I've had several bad motors that had that problem, and I had to replace the motor. I personally don't think this is the DCDS.
The motors seem to run fine on a 9V battery and there isn't any play I can feel in either motor.
On a positive note because your question had me remove the shell again it motivated me to replace the foam tape that was leaving me with dirty hands
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Images (1)
When it jumps like it does in the first video, can you see the flywheel with the magnet & sensor board on it bob up and down? …..this would be the end play John’s referring to. If so, the flywheel with the magnets is more than likely moving away from the sensor enough to cause an issue.
Pat
Another thing to check, is the magnet ring loose on the flywheel? If it's slipped down, it'll create the same kind of issue.
No bobbing and the magnet wheel is level with the bottom of the flywheel. I cleaned the sensor board and magnet wheel just to be sure that this wasn't a dirt issue. It's strange. In conventional mode if I throttle up slowly then the loco will start moving, but throwing the throttle up quickly results in the pulsing.
@Chris E posted:No bobbing and the magnet wheel is level with the bottom of the flywheel. I cleaned the sensor board and magnet wheel just to be sure that this wasn't a dirt issue. It's strange. In conventional mode if I throttle up slowly then the loco will start moving, but throwing the throttle up quickly results in the pulsing.
What’s the item #?
Pat
6-28521
It has the FM1 DCDS board in it.
If this has a switch for Oddesy on/off, turn it off and see if it behaves differently
Pat
This one doesn't. I think it's the generation before they added the switch.
Finally got to the bottom of this, the original motor speed sensor harness had a short where lionel spliced in the capacitor. Built a new one, and the pulsing is mainly gone now. A little bit left in conventional but the loco can actually be operated now.
@Chris E posted:Finally got to the bottom of this, the original motor speed sensor harness had a short where lionel spliced in the capacitor. Built a new one, and the pulsing is mainly gone now. A little bit left in conventional but the loco can actually be operated now.
Good find, also thanks for keeping all of us updated. May times people find the issue and just stop posting.
