Shopsmith will not start

[capnhook]

I have a 1967 Mark VII Shopsmith and it just stopped working. I push the FWD button and the REV button and nothing happens. I dismantled the machine enough to where I could put a continuity test on it and it looks like the switch may?? be OK. I got continuity between L1 on top and L1 on bottom of switch and same with L2 top and bottom. When I pressed OFF, no more continuity, so that part of the switch seems to be working. I don't know where to go from here. The motor does nothing. Just sits there. Any help?
Bryan

[JPG]

Before we go too far, does it have a start relay, or just a start capacitor? Also what brand motor?

The other terminals on the switch provide direction switching for the start circuit.

Does the motor hum when you attempt to start it?

[capnhook]

The motor is the A.O.Smith. It looks like one wire goes to the capacitor and the other goes to the motor. Do not see a relay. The motor just sits there. No noise, no nothing.

[JPG]

OK. A pix of the wiring and switch might help. I suspect incorrect connections.

We may need to measure motor wire continuity which will require removal of all wires from the switch.

[capnhook]

OK, can't do it right now, but those wires have not moved for 52 years. You will have to
tell me how you want me to check motor wire continuity. Will try to get some pix in AM.

[everettdavis]

OK, can't do it right now, but those wires have not moved for 52 years. You will have to
tell me how you want me to check motor wire continuity. Will try to get some pix in AM.

I have a restored Mark VII manual that discusses the 4 known motor types and has wiring diagrams.

What you likely have is a centrifugal motor start switch. They are spring loaded that forces a set of mechanical contacts open when the motor begins to spin. The springs return the contacts to closed position when rotation slows enough for spring to restore the contacts closed.

The motor start circuit is complete when they’re closed allowing the motor to start again. If it gets clogged up and mechanically cannot close, the motor will not start. It will hum, and burn up windings if not turned off quickly.

Look at the Mark VII Folder by following the My Google Drive link at https://www.shopsmith.com/ss_forum/view ... 90#p185690

If your motor is bad, there is s fellow eSimon on eBay who rebuilds motors including the Mark VII.

JPG has a very well done thread on the Mark VII he rebuilt. Very good resource.

Good Luck,

Everett

[garys]

If you have power to the motor and it doesn't run or attempt to run, then I agree with everettdavis. Check first for a centrifugal switch. They usually are under one of the end covers and slipped around the shaft. If you find one, check it for free movement and also check the contacts for burning or other damage.

[capnhook]

Here are the pix. I will try to find the relay and get back to you.

[capnhook]

I have done some more research and find that the version I have does not have a starter relay. I have a "motor start capacitor" and an "Internal Centrifugal Motor Start Switch". Could the capacitor be dead? That looks like it would be an easy fix (HAHA).
Thanks,
Bryan

[dusty]

It is an easy fix. Statistics might tell you that it is not the capacitor. Be careful of the two leads. When you first get the two wires disconnected- short them together like with a screw driver). From there, it is as simple as it looks.

Clean (like burnish) the relay contacts if the capacitor does not fix it.