20 Most Recent Makita 7 1/4" Circular Saw 5007NB Questions & Answers

generally on opposite side of trigger white on top black on bottom and ground on trigger side bottom

https://www.ereplacementparts.com/makita-5007nb-circular-saw-parts-c-97_98_101_109.html

Could be the cord. Could be the switch. Could be the motor.

I had the same issue. Turns out the brushes were fused into the brush mounts. I pulled on the copper end cap and wire only to break it off at the carbon brush end. I had to pull the motor out of the housing (stator) to expose the brushes. I then used a tool to push the carbon brushes back in and out of the brush mount assembly. You could also push from the outside in, just make sure you get all the carbon pieces and use a tool that won't put scratches in your brush housings. My brushes where well over 1/2 inch long....but they were just fused into the assembly, so the spring wasn't pushing it properly against the commutator, which I am guessing was the reason my saw just stopped in mid use....I had ripped a straight line in a board and stopped for a few seconds to reposition the saw only to find it no longer worked.

I don't mean to sound too patronising, but I get all sorts coming into my repair shop. Have you checked the continuity up to the switch, i.e through the plug and cable? Also, remove the brush caps but leave the brushes in place and check the continuity across the back of the brushes. There should be a circuit cross the motor, and if there isn't it is probably just that the brushes are sticking slightly due to sawdust. If this is ok, then remove the brushes and check continuity from the live wire (with the switch locked on) to one brush holder and then the other. You should only get a circuit too ne holder. The do the same with the neutral side. Again you should only get continuity to one holder (the opposite one to the licve circuit). If you don't get continuity both ways, and the switch is new, this would indicate an open circuit/loose connection on the field coil assembly. If the armature was faulty the machine would normally still run but with low power and excessive sparking.

It sounds as if you might have a little more wrong with the saw than just the brushes.

Things to check: With the saw running, safely grab the cord by the boot and pull and twist it around. This is where a break frequently occurs inside the cord and when the saw is held in certain positions the break will either open or close. If the cord's OK, unplug the saw and remove the brush caps and check the brushes. If the brushes are less than 1/4" long or the springs are burnt or broke they won't make good contact with the armature. If the cord & brushes are OK your next recourse is to replace the switch (Makita PN 651172-0).

Could be it's overheating. Clean out all sawdust from the vents on th e motor body, and wherever else you find sawdust. Check that you're using a sharp blade. Check all wiring connections are secure. You maay need to remove the cover behind the on off switch to check thatb all the push on connectors are pushed on tight.

I hope we're talking about the same nut, is it the one on the lever to lock the cutting depth? If so, it's held in place by a lock plate that you remove by taking out the small pan head screw next to the nut. After you take the lock plate off the nut should come off easily.