DM-28Q Dynamotor Startup

Finally got the DM-28 dynamotor for my BC-348 up and running. Had a big problem with a stuck brush. The brush wasn't making contact with the commutator. After a 2-week soaking in WD-40, the thing still wouldn't budge. I had to completely disassemble the dynamotor and drive the brush out from the inside. The unit was then cleaned, lubricated and reassembled. The bearings were cleaned in an ultrasonic tank with hot water, then were dried with high pressure air, followed by a baking under a heat lamp. I lubricated the bearings with moly-grease, being careful not to "pack" them, as so directed in the BC-348 receiver's service manual. This is the initial power-up.

[@rainerbohn3766]

Hey and greetings from Bavaria, Germany. Just overhauled a DM 28. Replaced the ball bearings by a modern Type 626-2Z from SKF.. What you assume to be commutator noise in my case turned out to be bearing noise. After replacing the bearings, my DM 28 is now quiet as a little mouse in the church. Best regards, Rainer, DJ9EP.

[@thinkapex]

What, no comments about your comfort working with high voltage? No smoke and flame?

[@N6MKC]

Ha! Yes, please observe all necessary safety precautions and remain hyper-vigilant when working with high voltages, such as those output by the DM-28 dynamotor. Thank you!

[@LaneyFamily16]

do you have plans for your power supply?