In my experience, the MMI motors are more robust than the EG motors but as you say, cost is an issue and is something to consider. I "suspect" that it may work, it is certainly worth a try. In all likelihood, your old motor burned out because the belt expired and the motor ran continuously. On most boomboxes, the deck cannot reset itself to the ready position as they require the energy from a spinning capstan to do that, and when a belt becomes loose, breaks or melts, then the motors just runs forever. BTW, older original mabuchi motors were larger. The new ones on the bay are smaller and more fragile than the old stock ones, and they are made in China. Pretty sure Mabuchi is a japanese company so you can assume they are counterfeits and probably won't last as long.
Here are some photos showing the difference between OEM mabuchi motors and the eBay China ones. Note that the original ones have the label on the rear while the eBay ones are on the side. Note the size difference. The mounting holes are in the same places but of course the OEM ones have more room between the holes and case edge. Note the difference in the bearings. Also note that the OEM motors have mabuchi stamped on the steel plate on the spindle side. The eBay ones just have label to identify that it is mabuchi. I have some OEM mabuchi motors remaining. Contact me if you are interested.
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