Help! Radial Arm Saw Repair

[Khb1526]

I need some help! I bought a used Sears 10" RAS(probably 80's model), but it is having a problem with the blade starting. I turn the power switch on and sometimes the blade will get going and other times the lights dim and there is a hum from inside the motor and the blade does not move.
When it makes the hum noise, you can give the blade a quick turn with a push stick and it will get the blade moving up to speed and will do fine. I have already replaced the start capasitor and it did not help. Are there any other suggestions besides taking it to a motor shop?

I am willing to spend a little more on it since it looks like it has had little use and I only paid $50 for the saw, plus $15 for the capasitor.

Thanks!

 

[Bigdog72]

Not really familiar with this but could it be the brushes?

 

[Glennbear]

Just a couple guesses:

Gunked up bearings from sitting unused?
(blow out housing with air hose)

Weak brushes like Geoff said.

A web search should lead you to an online copy of the owner's manual which you may find helpful. When you get it running there is a free safety upgrade kit available which includes a new table and guard assembly. :wsmile:

 

[Phil S]

I am fairly certain that motor uses a start winding and centrifugal switch to start up. At power up the start windings are connected thru the internal switch contacts. This switch opens up after the motor comes up to speed and then the normal run windings keep the motor running. The problem you are having is the motor is trying to start on the run windings - which it cannot do. The problem is most likely the switch contacts are burned or covered with enough gunk to not make contact. Hopefully you can disassemble the motor and clean them. hope this helps

 

[DIYGUY]

I second that and it is not a very hard thing to fix either. Luckily, Sears is still very good on parts if you need them. They also have their manuals online so you should have no difficulty in tracking down the little things that you might need. Another thought for you, is that CL has a Sears RAS for sale almost weekly, if not daily. It might be worthwhile to pick one of these up and cannibalize it for other parts along the way.

 

[Khb1526]

I second that and it is not a very hard thing to fix either. Luckily, Sears is still very good on parts if you need them. They also have their manuals online so you should have no difficulty in tracking down the little things that you might need. Another thought for you, is that CL has a Sears RAS for sale almost weekly, if not daily. It might be worthwhile to pick one of these up and cannibalize it for other parts along the way.

Phil s & DIYGUY, sounds like that might be the problem. It does not seem to be getting the extra kick it needs to get the blade started. I have taken off the cover to the motor housing and blew out as much as I could and took the starter switch out. Did not seem to do the trick, so I guess I am going to have to take the motor completely out of the housing and check all the connections. Don't have a lot of experience with motors, so wish me luck!

 

[Joe Scharle]

Sounds like mine if I don't use it for a long time. Rings stick in the cheapo slips, so I remove the blade; force a start; power on and off without letting the motor completely stop. After a few cycles it clears up til next time.