G1 Omega Supreme motor replacement

[bradm]

Hi All, really great forum! I was visiting my parents last weekend, and my mom gave me a box of my old toys to take with me. In it is my old G1 Omega Supreme. It's in really good overall shape, but the electric functions weren't working.
I took apart the switch and cleaned it, plus cleaned the copper contacts from the battery box on the top shell. The light in the head works now, but I've confirmed with a multimeter that there is power going to the motor but it isn't working.
The only markings on the motor are Mabuchi Motors and Taiwan. There's no indicator of its speed or any kind of a part number.

So I'm here hoping someone has a part number or even better a link to a replacement motor. The motor is 20.7 mm diameter, and the body not including the shaft and gear is about 24mm long. I've looked through Mabuchi Motor's small motor catalog and can't find anything. I'm not having any luck with general internet searches either because I have no idea what the rpm of the motor is.

I'd appreciate any help. I'm trying to get this otherwise great Omega Supreme from my childhood back in working order.

Brad

[Time Traveller]

Welcome, Brad!
Before you go through the trouble of replacing that motor, spin the armature by hand a few times to wear down any film of oxidation on the commutator and brushes. In all my years of toy repair, I've never had to REPLACE a motor unless it was severely rusted or corroded. Like, visible chunks of corrosion on the outside of the unit. Another trick is to stick a 9V to the contacts for a short time. I often do this to get toy motors running that don't have much visible corrosion. The 9V overcomes the physical and electrical resistance enough to get it spinning, and the spinning usually cleans up the rest, and it'll run on the 3V put out by a pair of AAs in series.
Let me know how this goes!

[bradm]

Great suggestion! Thank you. I gave it a few spins by hand. It didn't seem to drag or resist. I have a bench power supply. I hooked it up to the motor, started it at 3 volts and turned it up til the motor started moving at about 4.5 volts, then brought it back down to 3. It started howling like a bushing was bad, so I've soaked it down with contact cleaner. Quite a bit of pink/red came out with the liquid of the contact cleaner. I'm letting it dry well now and will try it again later. Thanks again for the tips!


Update - That did it! The electronics are all working.
Thanks again!

-Brad

[Time Traveller]

Hey! That's the success story I love to hear. For those who come by this thread later, a lot of motors that have too much "resistance" spin freely, it's just a surface layer of crap on the brushes and commutators inside. The bench power supply was a pro move in this case, but since most people won't have one, the 9V battery will do the trick provided you don't use it overly long. Usually it only requires a few seconds of spinning to get to the point where it'll run on the normal AA voltage (usually 3V for a lot of toys).
Contact cleaner was another great idea. I've also been known to dab the tiniest bit of lube on the tail end of the armature to quiet squealing motors.
Again, great job Brad, may you enjoy many hours of Omega slowly stalking around your home