electrical issue with a singer 15-91

**miyanc** · 03-23-2015, 22:14

Ok so I fixed my thread issues. I have 2 different 15-91's. Koolranch gave me one that he had restored but started smoking. I have one I rewired the motor on. I have the original wall plug and pedal from my 15-91. after I fixed the first machine I started on a few projects. As I was sewing the under part of my arm kept hitting the post you use to wind the bobbin. When I hit the post it felt like I was scraping a bur. I would check my wrist or the post and nothing. It happened several times and I could not figure it. Then afteri had sewn 3 inches into my dl project, thought maybe it was electrical. I got my fathers old meter and sure enough, if I held the negitive and touched the machine with the positive the needle jumped. So I checked all my wiringand could see anything off. I checked the pedal and wall plug and it again looked fine. I pulled up the wiring harness images and dOuble check to make sure it was correct. Now I am further down the rabbit whole then I wanted to. Still wanting to figure this out, I figured I would wire my pedal and use the other singer. At first I could not repeat the issue. I decided to make this machine work and switched whats needed. I got tjis machine going and noticed a little smoke, which looked and smelled like a lionel train. It was very minor when I first started but I moved on. Now using the other machine I hemmed the sides of my argon 1.6. During use I started to feel the tingle again. I finished the hems and checked the meter and we are back to the same thing as the other machine. I had tried to check several times during use and at first I could only get the needle to move when the pedal was engaged. Then after a while I checked and it was happening even after.

My first thought was the pedal. Although both machine are rewired they were done by 2 different people. I would assume it would seem less likely we both made the same mistake. I am using the pedal for both machines.

I was hoping to finish my project by friday. I put my diy stuff off because I truly enjoy these machines and fixing things, I just wanted to make my gear. I have people wating on my and almost no money. Koolranch has another machine I can buy, I could buy a pedal or even the wall plug but I cant do it all.

I may also just stop into the repair shoppe tomorrow and aSk. I also dont want to dump money on a service repair.

Thanks for reading and helping. I guess I snould be luck I didnt get the aed treatment.

**gmcttr** · 03-23-2015, 23:08

You can wire the speed controller (pedal) or the speed controller (SC) 3-prong connector wrong and it won't energize the sewing machine body.

You have to have a short to the body at or beyond the machine side of the 3-prong connector.

If the body remains energized without the SC being pressed, either the SC is adjusted wrong and always allows some current to flow or the short-to-body has to do with prongs 1 or 3 of the 3-prong connector on the machine side or beyond with the light wiring as these are always energized.

Originally Posted by miyanc

...I decided to make this machine work and switched whats needed. I got tjis machine going and noticed a little smoke, which looked and smelled like a lionel train. ...

Where did the smoke come? More than likely it was oil burning off of the motor armature/brushes and had nothing to do with the electrical problems.

What parts did you transfer to the second machine?

Was the wiring from the motor to the 3-prong connector replaced on both machines? Same question for the light wiring.

**miyanc** · 03-23-2015, 23:42

Originally Posted by gmcttr

You can wire the speed controller (pedal) or the speed controller (SC) 3-prong connector wrong and it won't energize the sewing machine body.

You have to have a short to the body at or beyond the machine side of the 3-prong connector.

If the body remains energized without the SC being pressed, either the SC is adjusted wrong and always allows some current to flow or the short-to-body has to do with prongs 1 or 3 of the 3-prong connector on the machine side or beyond with the light wiring as these are always energized.

Where did the smoke come? More than likely it was oil burning off of the motor armature/brushes and had nothing to do with the electrical problems.

What parts did you transfer to the second machine?

Was the wiring from the motor to the 3-prong connector replaced on both machines? Same question for the light wiring.

I will start at the bottom. Yes the wiring from the motor to the 3 prong on both. On the first machine I removed the light when I did the wiring. I have better lights and didnt want to spend the time redoing it. On Koolranchs machine hehad the light.

I moved the pedal, wall plug, thread adjuster and bobbin.

Yes I felt the smoke was burn off, which is why I felt comfortable running the machine. Until the wiring use popped up on this one too.

So if its a short from 3 prong towards the motor its on both machines. I didnt take the second machines motor apart or even check the wiring farther then the 3 prong. On mine I pulled the whole thing mostly apart. And unless the short is in the section from what I wired up to the motor, I am not sure what it could be. My wires were purchases as a kit and the heat shrinks are in tacked. The instruction say to leave enough to work with when cutting.

I will look further into these areas tomorrow. Does anything I have said made sense so far? Switching and nor shorting, then shorting but first not until I hit the pedal ( its the stock knee pedal.

WV · 03-24-2015, 09:00

Sorry you're having problems, but glad you're posting. I've replaced the power cord on my 15-91 because the insulation was cracked. Someday I'll need to do more of electrical repairs.

**miyanc** · 03-24-2015, 09:46

Originally Posted by WV

Sorry you're having problems, but glad you're posting. I've replaced the power cord on my 15-91 because the insulation was cracked. Someday I'll need to do more of electrical repairs.

I already wired the motor ( maybe incorrectly) and believe gmcttr that logically it would be from the 3 prong towards the motor. I guess if it was the plug or the pedal it would be more local to those items. I am glad it wasn't worse and in many ways just want to keep using the machine. I small zap is ok I just don't need the full monty.

**Spark** · 03-24-2015, 17:02

Here is a manual. http://parts.singerco.com/IPinstManuals/15-91.pdf

**miyanc** · 03-24-2015, 18:38

Originally Posted by Spark

Here is a manual. http://parts.singerco.com/IPinstManuals/15-91.pdf

Ty sparks.

**miyanc** · 03-24-2015, 19:09

Ok I took the engine apart on my machine and with a very bright light I can see 2 very small flashes of medal. I need to either get a little more heat shrink something else.

**miyanc** · 03-24-2015, 21:16

I tried to use the heat shrink but if you cut it then heat it it retracts. So I used electrical tape to see if I could put it together and check. I know its not a permanent fix.

So first question is should there be any current running thru the unit when its either running or plugged in?

Second question, other then cutting and re soddering the lines, what can I use to reseal the lines. Like the heat wrap.

**miyanc** · 03-24-2015, 21:45

I am also not sure I am reading this analog meter. I know enough to use it just not in reading and knowing what it means 100%. In other words I can plug in the probes and have it set to ac v. If I ground the black and touch the machine the needle moves. This ment something when I was getting shocked. I have now repaired what I think is the issue and in returning the machine the needle still moves but not even close to what it was doing. I know enough to know just because the needle moves it doesnt mean bad. For example the disc I touch to cycle my shop lights also moves the needle, but thats how it cycles.