Help With Sewing Machine Repair?

[angelatc]

Anybody dabble in primitive electric gadgets? I have a vintage sewing machine that is always on. If you don't know sewing machines, there's usually a foot or knee pedal that powers the machine. The harder you press the faster the machine goes. If you don't press the switch, the machine should be off.

Here's the old school metal foot pedal.

Here's the inside:




When I opened it I expected to see the bar not fully disengaged, but it is. Then I took the whole inner unit apart thinking there would be a mouse or something shorting across the coils, but nope. I looked under the pivot point of the bar to make sure there's no contact there.

I am stumped. I cannot figure out how the motor is getting power. Any thoughts?

[luctor-et-emergo]

Do you have a multimeter ?

[Anti Federalist]

Each one of those coiled wires is a resistance coil...varying degrees of resistance to the motor result in slower or faster speeds, but I'm sure you know that already.

My first guess is that one of those has broken/burnt out/gone bad.

A visual inspection may not reveal one that has failed.

If you have a meter, check (carefully that looks like 120 VAC) across the riveted contact points, the swing arm and terminal.

If there is, the contact point in the swing arm may have failed. Check for continuity between the swing arm and the lower terminal screw.

[dannno]

A sewing machine that is always on.....can I have its number?

[luctor-et-emergo]

Each one of those coiled wires is a resistance coil...varying degrees of resistance to the motor result in slower or faster speeds.

My first guess is that one of those has broken/burnt out/gone bad.

If you have a meter, check (carefully that looks like 120 VAC) across the riveted contact points, the swing arm and terminal.

If there is, the contact point in the swing arm may have failed.

I would recommend to measure resistance when it's not plugged in. If the resistance is unlimited there is no connection.

[Anti Federalist]

I would recommend to measure resistance when it's not plugged in. If the resistance is unlimited there is no connection.

A much better option, yes, this.

I'm going to guess that, if the machine won't work at all, and assuming it's not anything "downstream" (motor, connections so on) that there is no contact from the terminal to swing arm.

[angelatc]

Of course I have a multimeter. What kind of a woman do you think I am?

[Dr.3D]

I suspect the cord has a short in it.

[pcosmar]

I am guessing insulators on the actuator shaft are missing or faulty,,, and allowing direct current on.

just a guess from pics.

[TheTexan]

Did you try turning it off and on again?

[Cleaner44]

I suspect the cord has a short in it.

I suspect Miss Scarlet in the Library with the Wrench.

[angelatc]

A much better option, yes, this.

I'm going to guess that, if the machine won't work at all, and assuming it's not anything "downstream" (motor, connections so on) that there is no contact from the terminal to swing arm.

The motor is always on despite the fact that there isn't a connection to the swing arm. I thought for sure I'd find the swing arm making contact, but it isn't. I think I might have to physically trace the wires.

If you don't sew, you might not be familiar with the layout, but under the chassis there's an outlet that has a cord that would run to a wall socket. Two things plug into that: the foot pedal/motor and a light. I am not using the under-chassis outlet. I plugged the foot pedal directly into the wall to presumably take the outlet and the light out of the equation, but now I wonder....if someone wired them in series, that might be the issue.

[angelatc]

Did you try turning it off and on again?

I see what you did there, and I am out of rep.

[phill4paul]

The motor is always on despite the fact that there isn't a connection to the swing arm. I thought for sure I'd find the swing arm making contact, but it isn't. I think I might have to physically trace the wires.

If you don't sew, you might not be familiar with the layout, but under the chassis there's an outlet that has a cord that would run to a wall socket. Two things plug into that: the foot pedal/motor and a light. I am not using the under-chassis outlet. I plugged the foot pedal directly into the wall to presumably take the outlet and the light out of the equation, but now I wonder....if someone wired them in series, that might be the issue.

I'm gonna go with this. I noticed the two cords entering into the stand in your picture and was wondering what the set-up under there was like. I'm also pretty sure that those cords should be run through the hole and not under the machine to stand contact. Or at least it looks like a grommet hole from the photo.

[Dr.3D]

I suspect Miss Scarlet in the Library with the Wrench.

If the cord between the foot peddle and the motor has become short circuited so as to cut the switches out of the circuit, it would make the motor run full speed.

[angelatc]

I'm gonna go with this. I noticed the two cords entering into the stand in your picture and was wondering what the set-up under there was like. I'm also pretty sure that those cords should be run through the hole and not under the machine to stand contact. Or at least it looks like a grommet hole from the photo.

Heh. Turns out the hubby doesn't know how sewing machines work. (I'm actually totally cool with that!) And this one has a slightly different configuration than the others I've seen.

I pulled out all my tools. Wire cutters, VOM, screwdrivers, wire nuts....then saw the foot switch wasn't connected like I pictured it. Turns out he was plugging the motor straight into the 120, bypassing the switch entirely. All repairs should go so smoothly.

[Suzanimal]

Heh. Turns out the hubby doesn't know how sewing machines work. (I'm actually totally cool with that!) And this one has a slightly different configuration than the others I've seen.

I pulled out all my tools. Wire cutters, VOM, screwdrivers, wire nuts....then saw the foot switch wasn't connected like I pictured it. Turns out he was plugging the motor straight into the 120, bypassing the switch entirely. All repairs should go so smoothly.

Good. Are you refurbing it to sell?

[phill4paul]

Heh. Turns out the hubby doesn't know how sewing machines work. (I'm actually totally cool with that!) And this one has a slightly different configuration than the others I've seen.

I pulled out all my tools. Wire cutters, VOM, screwdrivers, wire nuts....then saw the foot switch wasn't connected like I pictured it. Turns out he was plugging the motor straight into the 120, bypassing the switch entirely. All repairs should go so smoothly.

Lol. Shoulda kicked the tires.

[NorthCarolinaLiberty]

It's probably out of gas.

Did you check the tank?

It's probably out of gas.

[oyarde]

I have always had the opposite problem with the Mrs.'s old machines, foot pedal not working at all.I usually throw them in a pile for parts and buy one off the net and replace it . Like yours , if she has any on all the time , probably because I wired it that way . It is not like working on a tractor , I do not try them out when I get done and I try to do it when she is not here because her office is somewhat small and she would feel the need to stand over me and block my light while talking about some crazy stuff which can be distracting.

[Danke]

Is it plugged in?

[Anti Federalist]

The motor is always on despite the fact that there isn't a connection to the swing arm. I thought for sure I'd find the swing arm making contact, but it isn't. I think I might have to physically trace the wires.

If you don't sew, you might not be familiar with the layout, but under the chassis there's an outlet that has a cord that would run to a wall socket. Two things plug into that: the foot pedal/motor and a light. I am not using the under-chassis outlet. I plugged the foot pedal directly into the wall to presumably take the outlet and the light out of the equation, but now I wonder....if someone wired them in series, that might be the issue.

I'm actually very familiar with these types of controls and handy around a sewing machine.

Sounds like you got the problem taken care of.

Let us know how it worked out.

[angelatc]

Good. Are you refurbing it to sell?

Absolutely! I can't keep them all.

[angelatc]

I'm actually very familiar with these types of controls and handy around a sewing machine.

Sounds like you got the problem taken care of.

Let us know how it worked out.

It was clearly operator failure. My fault as much as his. He brought me over to show me the issue and I immediately got it in my head that the foot pedal had issues without looking at the bigger picture.

Worked out ok - the store is pretty cluttered so I got to sit outside for a bit and test it. IN my life, that's practically a vacation.

Thanks to all of you for your help!!!