Lionel KW Transformer Rectifier Disc Replacement

Before diving into the KW, service the whistle first.

This entails pulling out the old cat and dog hair/fur(from long-ago-dead 50+ years pets) and the tinsel, pine needles and spider webs out of the impeller with a fine tool, and use pressurized air from a compressor to clear the whistle chambers of similar debris.

Completely service the whistle motor including lubricating both ends of the armature and using new brushes after a thorough cleaning of the motor, commutator, and the gaps between commutator segments. 

The lower bushing/bearing between the armature and the impeller can be accessed with a needle oiler  looking down through two of the armature poles.  This one is often missed.

Also, for the KW, clean the contacts for the whistle control, I use a generous shot of contact cleaner.  Many times that's the issue and not the rectifier.  The fact that the locomotives slows with the whistle control suggests the second stage of the whistle control contacts is not making it, they parallel the low value resistor across the rectifier to boost the voltage to compensate for the power the whistle tender draws.

Thanks, will definitely keep this in mind.

Thanks You,

John

The tender whistle unit has been serviced when I recently purchased it.

Thanks,

John