Shopsmith Forums

JPG wrote:Yes it makes sense.

We have reached the point where visual inspection is not revealing any clues.

That takes us back to measuring resistance etc..

Harbor freight often has a multi tester on giveaway.

The closing of the contacts would be indicated by a near zero resistance reading.

The start winding resistance would be a few ohms.(<10)

Checking the capacitor is more tricky.

I picked up an ohmeter today. Will search for how to do the proper checks. I do not have a lot of experience with the ohm meters.

So I took readings today at the c Switch, the capacitor and the power switch.

Centrifugal Switch: I placed the two probes at the contacts of both leads on the switch and get a 0 Reading.

The Capacitor: Probes on opposing terminals and the reading jumps anywhere form 200 to 1200 then back to zero.

Power switch: I placed probes on the Green wire and the top white wire. I get a pulse then back to zero. Touching all other points I just get a zero with no activity.

Any help is still obviously greatly appreciated and I will gladly provide pics if needed.

I think you just determined it is the power switch that is malfunctioning.

I am concerned re a GREEN wire being connected to a switch terminal.

Please tell us what wires go where on the switch.

To keep the nomenclature straight, identify the switch terminals as: end left or right and center left or right. That describes a 4 terminal switch.

If the switch only has two terminals than end and center will suffice.

There are three wires in the power cord.

There are two wires from the motor.

The green power cord wire should ONLY connect to the case of the motor.

I have attached a photo of the Switch. I apologize, the "green" is apparently blue. but as you will see it looks almost green on mine now due to age.

I ran the readings again. All go to Zero, the bottom right White to Motor is the one who shows some activity then goes back to zero. the others just remain at 0

I have not read the entire threat but your notations on this one with the switch image indicates a bad power switch; can not turn unit off.

Pull the wires off (picture shows how to put them back on) and then measure the switch only in the same way.

With switch on, I would expect you to get the same readings. With the switch off, you should get entirely different readings. If the readings are the same, then you definitely have a bad switch.

For a 'properly' operating switch the following readings should be observed.

With switch OFF:
1) No continuity between cord black and motor blue.
2) No continuity between cord white and motor white.

With switch ON:
1) Continuity between cord black and motor blue.
2) Continuity between cord white and motor white.

Neither should break continuity when switch moved/banged/wires pulled etc. i.e. both should be a solid one.

Continuity between the motor blue wire and the motor white wire should ALWAYS be near zero.

While checking the switch, also check the cord.

With switch OFF:

Continuity between the cord black wire and one of the plug flat blades.
Continuity between the cord white wire and the OTHER flat blade on the plug.

Look for any tendency for the readings to change while measuring that are not a result of probes slipping.

Great info, thank you Will test here today again.

Dusty
I have a unit on my bench right now that has a green wire connected to the motor. It is an AO SMITH motor. The first one that I have worked on. When I pulled it apart I did not notice the wiring. I am familiar enough with wiring to figure it out. The green wire could be a faded blue but it sure looks green in the fluorescent light in my garage.

Fairly Certain that is the same motor and wiring I have in the pics.

JPG wrote:For a 'properly' operating switch the following readings should be observed.

With switch OFF:
1) No continuity between cord black and motor blue.
2) No continuity between cord white and motor white.

With switch ON:
1) Continuity between cord black and motor blue.
2) Continuity between cord white and motor white.

Neither should break continuity when switch moved/banged/wires pulled etc. i.e. both should be a solid one.

Continuity between the motor blue wire and the motor white wire should ALWAYS be near zero.

While checking the switch, also check the cord.

With switch OFF:

Continuity between the cord black wire and one of the plug flat blades.
Continuity between the cord white wire and the OTHER flat blade on the plug.

Look for any tendency for the readings to change while measuring that are not a result of probes slipping.

See attached Testing this now.