To the OP, electronics as you say will sell well, though the margin will be smaller. At the end of the month, it really is all about the bottom line. I think you have to determine what is more your selling style. If you like quick turnaround, it sounds to me you are doing a good job already. Why fix it if it aint broke?
Sure there are other items that may have a higher margin, but what if you don't sell it? I guess you just have to evaluate all your options, but at this time it seems like you are doing well with electronics.