Internal Singer motor wiring

The machine was a Singer 201K3 but all Singers can have the same problem as this one.
When you come across an old Singer motor (1950s or older), it should be inspected thoroughly. If you have no idea what you're doing with electrical things, motors powered by mains voltage aren't a good way to start learning. Don't just plug it in and turn it on. While I'm on the subject, if the motor is hard wired (like the early ones), don't just switch it off, unplug it too. You'd be shocked to learn that the electrician crossed the neutral and live wires on that power point (pun intended).
Being someone who has quite a lot of experience with electrics, I removed the carbon brushes - remove them and put them somewhere so you can put them back in the exact same side and position as you removed them. If you put them back differently in any way, they won't make contact as well as before and the motor will be weak for a while. If they're short, you should replace them. They're only a few dollars and if you wear them out the springs will damage the commutator.
I then took the motor apart and the stator (the bit that doesn't move, also called the windings) wiring was as per this photo.

The wires (black and red)

In case it's not obvious, these wires are not fully insulated. I touched them a few times and the remaining insulation fell off. So where to now?
If you're not also extremely competent, confident and comfortable with electrical work, you have these options:

1.  Take it to a small appliances shop and have it repaired.
2. Have the motor reconditioned (re-wound) by a motor repair service (they do exist).
3. Swap the motor with a known good one (or a new one, but be careful, new Chinese made motors are often as dangerous as the one above).
4. Take the motor and light off, replace the hand wheel and pop it into a treadle cabinet.

Assuming you're all good to continue, you need to now make these two wires safe.
You will need a soldering iron, solder and some heat shrink tube insulation. If you don't have the latter, get some or you won't be able to complete this. Do not use electrical tape. It will melt off as soon as the motor gets warm, as will anything else. The heat shrink tubing needs a soldering iron's heat to shrink and will only melt if you burned it in a fire.
The rest of the wiring in the stator is held in place and not insulated with rubber, so we don't need to worry about it.
At the brush mounts, the wires are soldered to a copper ring, which is in turn soldered to the square brush contacts, which you can see in the picture is on either side of the hole at the end.
I was not able to remove the copper ring because of the amount of solder, so I cut it as close as possible.
Remove any remaining ' insulation'.
Now, cut a piece of the heat shrink insulation that will fit as snugly as possible over the bare wire and shrink on some new stuff (use a less hot part of your soldering iron and gently stroke it on all sides until it's hugging the bare wire).
Now solder it back onto where you cut it.
Do as Singer originally did and smother the whole end of the wire with solder. This is difficult because you need more hands than you were born with but you need to make sure these wires will never come loose.
It's unlikely they'll ever be pulled because only the rotor (armature) moves and you're going to ensure that it doesn't move anywhere near these two wires, but make sure it doesn't come off as you reassemble it.

Afterwards. Apologies for the fuzzy photo

I wasn't entirely happy about that millimetre of red wire that is exposed but there's absolutely no chance of it ever touching any conductor.
Repeat with the other wire then clean the commutator (the copper strips that come in contact with the carbon brushes).
Now reassemble the motor body, while watching the wires carefully as you put the end on. The wires will move differently now that you've changed the insulation. Make sure that the whole soldered area easily clears both the rotor's wiring coils and its contacts (the copper strips). I stress easily because the wires could settle slightly and move a little more when the motor warms up. Just imagine all that could go wrong and check that you've made sure it can't happen. It doesn't matter that it's a thousand times safer than before if it electrocutes someone because you didn't put enough solder on, left too much wire bare or used electrical tape. Do everything and your conscience will be happy.
So it was much more work than I expected, but I was extremely happy with the result. This motor should last many decades without anything more than the occasional set of carbon brushes. 

Servicing your 201K part 1

In Australia and in the U.K. there are loads of these machines around. There were literally millions of them made because they were so good Singer made them from the 1930s until the 1960s. A straight stitching machine in the 1960s that cost more than any zig-zag, free arm machine and people still bought them. Why? What's so good about them?
Firstly, Singer made these with special hardened steel gears, so they were as tough as nails. They had an incredibly simple system of getting the bobbin moving (just one bar underneath the machine) which performed a perfect stitch on both the top and bottom, and it could stitch everything from silk to leather. Just about any machine can be made to sew through leather but the 201K can do it easily**.
** As a side note, sewing through leather is easy enough, but leather tends to get dragged back by the presser foot and will bend and break your needles as well as screw up the stitching (and with leather, there's no second chances). To properly sew leather on a sewing machine you need a walking foot (even feed foot) which moves the work from the top as well as the bottom (the regular feed dog), or a wheel feed and foot, which Singer made several models of.

Now, next thing you should know is that the 201K has two forms: The early cast iron one and the later aluminium one. Here they are:

1936 201K3 cast iron weighs a ton!

The 201K23 (201P) weighs half as much

They look radically different because aluminium is so much weaker than iron that Singer had to redesign the head to make it stronger. The stitching mechanism is identical in both machines.
Technically the cast iron version is a 201K3 and the aluminium one is a 201K23, but it's really not important.

Electrical first

Okay, so you have your 201K on the bench, what's the first thing to do? Firstly, check the wiring, particularly between the motor and light. You can see that the one in the photo isn't that great, but I'm aware of it and will be replacing it. Replacement is not trivial and I have a blog entry devoted to this. See here for replacement of the Singerlight wiring.

This is usually the wire that goes first

Check both sides of the bakelite plug

1950s vinyl insulation does not last forever, especially in Australia. It cracks and flakes off. I heard recently from a guy in NSW who said that all old Singer motors are death traps and none of them would ever pass a safety inspection. He has good reason to say that: He imports and sells cheap quality Chinese replacement motors.
Here is my experience: I have fixed literally hundreds of electrical machines and none has ever been a problem. Also, I had one that had been tested and had a safety tag on it when I bought it, so I don't really believe this. If you choose to buy a second hand sewing machine that doesn't have a safety tag on it, you are expected to take full ownership for getting it tested, and the device will have a label saying just this. You have been warned. If you don't know what you're doing and the wiring is suspect, don't plug it in or you might kill yourself.
The wiring is by far the most important thing to check in the same way the brakes are if you buy a second hand car. It's the thing most likely to injure or kill you if it's not good.

Foot Controller

These came with radio suppression capacitors, which are a problem when they fail. Their purpose is to suppress AM radio interference and they also suppress some of the sparking inside the motor. When they fail, they bridge the electrical connections inside the controller and your machine starts sewing at full speed all by itself! All sewing machine repair people I know remove the capacitors. I wrote an earlier blog entry here on these, and the example was the twin capacitors. Here is the procedure in pictures for the single capacitor version:

turn over, remove screws, push the button on the other side

It's the grey thing. I've disconnected one side

disconnected. It would work perfectly well now, but remove it

before putting it back, drop of oil here and around the button

Repair of 1950s Singer motor

I met a fellow blogger the other day at Spotlight (Vogue pattern sale) and surprising number of amazing patterns left at only $5 each. Yes I know (bought 27), but I digress. She (thornberry.blogspot.com.au) told me to write something as I've been a bit slack recently.

So a few days later a lady from an FB group asked about repairing her older machines. Yes indeed there should be more information about this, so here is the most common electrical problem I've found with Singer motors: The wiring for the singerlight (that's what they were called by Singer) degrades and the wires touch, causing drama and blow fuses.

Warning: My friend Cyndy asked me to make an instructional piece on doing this and to make sure I warn people not to do this unless they're completely competent, familiar and comfortable with all of these concepts. I usually assume that people already do this, but she's right: Please don't play with electrical things if you have any doubts at all.

Here's the before picture (bit out of focus but still obvious what the problem is). This one is nowhere near as bad as I've seen. A lovely friend gave me a 201K23 for my birthday and the wiring was absolutely gone, and I mean no insulation left, wires totally touching each other at several places. This one would have been completely fine for decades, as the rubber insulation was completely intact, it was just the green outer that had gone. Pretty unsightly and looks dangerous, and I want to sell the machine (a 320K2). The rest of the power cable had already been replaced with the standard black.

Singer motor and light, connected by degraded flex

1. Remove the light. Prise off the end: This just pulls away with the lense still on. After this remove the bulb or it will get broken.
2. Unscrew the plate that's covering the light's mounting screw (already removed in the picture above) then remove the mounting. Put all screws back so you don't mix them up. That is, as soon as you remove the light, put the plate back.
3. Remove the motor screw then remove the motor from the machine and put the screw back in.

Now the motor and light have been removed as a unit. Put the machine out of the way until you're ready to put it all back on.

4. Disassemble the light.
4a Circlip 1. Just take a small screwdriver (jeweller's or the one for adjusting the bobbin) and unclip that circlip in the picture. This is one of two things holding the light fitting in one piece, there are no screws, just two clips.
4b Other clip is here:

Original was green, but snapped when I tried to remove it :-(

This clip is much harder to move. You don't have to remove the screw, but make sure you only turn it so the spring holds it less tightly. In the picture that means pushing the bit with the screw upwards. You need only a little turn, so the arms (already removed) can be pulled out. Pull them out. They will be pretty tight and they're sharp-ish, so try to grip them hard then pull away as you did the lense.
Now you can turn the clip and prise it off. Once off the light will separate into two.

Again, this is an after shot.

This is what the inside looks like. The wires (originally yellow and red) are soldered to those copper strips. Remove the copper strips with the wires attached.

and again

Unsolder the wires. This is a little tricky because you need dexterity holding, soldering and pulling at the same time. Make sure you remove all the solder, because the new wires have to go all the way through these holes.
The other ends are on the motor. Unscrew the long screws holding the wiring cover on. Remove the cover and the piece of cardboard and you should be looking at this.

well not quite: again this is an after shot

Unscrew what you need to and put the nuts and washers somewhere safe. The original wires are clamped and soldered to little circular washers. If you have these, use them. I don't.
Now you should have the original wires in your hand. You need to cut the replacement wire to the right size. Better to err on the larger side. Remove sufficient insulation and bare enough wire to wrap around the two posts on the motor.
Solder the new wire to the copper strips from the motor first, and before you install the other end in the motor, make sure you have both the light circlip and the white plastic motor wire clamp in place . The latter goes into the hole that the screw secures in the above picture (on the right). You don't want to leave either of these off.

Wires are now secure on the motor end

Put the white plastic back in its place and secure it with the screw. Reassemble the motor wiring cover.

All in place

With the cardboard insulation

Ready for the screws

Now the light end. Solder the copper wires to the copper contacts and insert them back into the light assembly. You might have to play with the switch a little to get them in. I used long nosed pliers. Don't bend them, you shouldn't need to force them at all.

Now it's just a matter of putting it together, replacing the circlip - you can push it over the lip and into the recess with your thumbs.

The next bit requires some force. Make sure you know which way to put the front light clip by lining it up on the machine. If you put it on backwards you'll get really upset. Put it on but not in exactly the finish position. It has to be off by a bit for you to reinsert the arms. Once you do this, turn the clip until it clicks into its groove and put the bulb and lense back.

If you screw this up, just have patience. I've done this a lot of times, and know it well. If you make a mistake, you'll probably not do the same thing again. It'd hard not to get angry if you do though :-).

Ready to go back on the machine

Doesn't it look nice? New plastic wiring should last a very long time indeed. I chose cord that has copper inside. Not sure if it makes a lot of difference but it shouldn't degrade over time.

Before putting it back on, check the brushes. These are small blocks of carbon whose purpose is to make electrical contact with the armature (of the rotor, rotating part in the middle of the motor).

Here's how to check the brushes. You're checking the size, and you can check how dirty the armature is too.

Remove the caps from the end of the motor - these are visible in the above picture. Take out the screw and you should be looking at this:

Exposed brushes

You can see the copper thing here. I pushed it up a little to make it clearer (which it didn't), but power is supplied from the wires on the right, which are soldered to the J shaped copper bit. The brass case is conductive and contains a metal spring pushing on the black carbon brush. The copper thing at the bottom is the motor's armature. This brush has already been checked and is fine. Check them every service and if less than half this length, replace them both. Don't take them out unless you have to: The ends are shaped as a curve by the armature and if put back differently you could easily lose power in the motor because the contact isn't as good.