I just got an all yellow brother. Thank you for the review!

I have a "Modern Electric" (that is the model name?) sewing machine made by Precision from before 1954 that is definitely a Class 15 clone and is very similar to your Brother. Straight stitcher made in Japan. Needs to be threaded on the side though rather than the front. I have looked at hundreds of images of Japanese machines from that era but have not been able to find another one. I am in the process of sprucing it up and also rewiring it (insulation was crumbling). The previous owner did not really maintain the machine but also treated it very kindly and protected it from getting damaged. The paint is almost in perfect condition and after some fuzz removal and oiling the machine moves/runs super smoothly. The belt on the machine when I bought it was a round one and it was close to breaking. I replaced that with another round one but it looks to me that it needs a v-belt. The round one slips a little. I assume your Brother takes a V and the profile of your motor and machine pulley look like mine. Would you know what kind of V belt your Brother takes? Thanks!