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How to fix a Brother KH930 Knitting Machine with “wont turn on” or “no power” fault

So you have a Brother KH930 Knitting Machine that you have let the smoke out of, and now it wont turn on, beep, boot up, power up or respond to any hitting or cursing. As is commonly known, all electrical items actually run on smoke, once it comes out, the item will not work. :) I found it was some small capacitors that released the smoke on this knitting machine.

My mother had collected this KH930 after it had stopped working, hoping I might be able to fix it. The previous owners had removed the needles for use as spares on other machines, that is why there are none in the photos. You do not have to remove the needles to perform this repair.

This fix may work for other models too, I would guess any that have the power lead that plugs directly into the side of the knitting machine. Not ones that use a “plug pack” or “power adapter”. 230/240/250v AC models should be the same components, 110v I don’t think would be the same value capacitors.

WARNING: Seek professional advice if unsure! 240v is dangerous.

Always unplug the knitting machine, or anything electrical for that matter, before opening! Switch it on and off (while unplugged) a couple of times to help discharge any electronic components that may hold a charge. Even though I had no issues with this repair, I will not be held responsible for any injuries sustained performing this repair.

Very basic soldering skills are all thats needed, and if you have never used a soldering iron before, it is quite easy to learn, just grab a cheap fine tipped soldering iron (under AU$10) and I think you will do OK! I will try to get a video online soon showing the basic skills required.

Each photo can be clicked on to enlarge, click the “BACK” button on your browser to return to the page.

Brother Knitting Machine Repair 01 - ToolsWe may as well go into the tools required for this particular job.
1. A fine tipped soldering iron suitable for electronics.
2. Some suitable solder (mine says 0.71mm diameter, 60% Tin, 40% Lead).
3. A Number 2 Phillips Head Screwdriver (maybe a smaller one too depending on your machine).
4. A small flat blade screwdriver.
5. Small sidecutters
6. Very narrow blade (optional)
7. Adjustable work holder (optional)

Step 1: Disassemble the Knitting Machine.

Brother Knitting Machine Repair 02 - Remove Plastic Rivets Brother Knitting Machine Repair 03 - Remove Plastic RivetsCarefully turn the machine over. At the end where the power lead plugs in you should see the 2 plastic rivets indicated. Carefully slip a fine blade under the edge and lever outward. The second shot shows how the plastic rivets work. The centre/cap slides out leaving a small hole in a smaller part of the rivet, remove the smaller part too. There is one to remove on the back of the machine also. 3 plastic rivets in total.

Brother Knitting Machine Repair 04 - Remove Screws Next, flip the knitting machine back over to the correct side facing up and remove the 3 screws from the bed. Take note of which screws come from where, they are different! On the Brother KH930, the 2 in the main bed are countersunk, the one near the gate pegs is ‘pan head’.

Brother Knitting Machine Repair 05 - Seperate machine end Slowly work the plastic end of the knitting machine apart from the metal bed. The power switch may want to stay behind, thats fine, it should wiggle free eventually, it is held back by the transformer inside.

Brother Knitting Machine Repair 06 - Remove Power Screws Next, remove the screws holding the power socket in place. There is actually a metal plate around the back of the socket so as you unscrew, it sort of feels like the screw is just spinning because there is no outward pressure to push the screw out. You can see inside that unscrewing is pushing the metal backing plate backwards instead. Keep going until it is free of the screws.

Brother Knitting Machine Repair 07 - Cable retainer Inside where the power cables go, there is a plastic retainer with two screws holding the cables in place, remove the screws to release the retainer and allow the circuit board to slide out of its little hidey hole. Take a mental note of which way up it fits in. Set the plastic case aside.

Brother Knitting Machine Repair 08 - Board Now we can see the top of the circuit board. The fuse can be popped out (it was blown) and the capacitors were visibly damaged, one of them was split open. Luckily the details of the capacitors were still legible, take a photo or write down the details before touching them as they may turn to dust when touched and those seemingly random numbers and letters are very helpful! If you live near an electronics store, take the components with you once they are removed. Hopefully the sales people will know what to replace them with. The 2 capacitors and one fuse should cost you much less than AU$10. I got 5 of each for AU$15.

Brother Knitting Machine Repair - Caps New and Old The Brother KH930 Knitting Machine I am working on used one 0.047uF 250V AC Mains, Metallised Polypropylene Capacitor, X2. One 0.1uF 250V AC Mains, Metallised Polypropylene Capacitor, X2. Oh, and one 500mA M205 Quick Blow Fuse, 5mm round x 20mm long.

The Soldering Stage

Brother Knitting Machine Repair 09 - Remove Capacitors Plug in your soldering iron, the fun is about to start! Make sure it is away from anything that might melt or catch on fire, including children. As long as the tip stays up off the table by about 30mm, it should be fine. If you have a brand new soldering iron, touch some solder onto the tip until it melts and coats the tip a bit, this aids in the transfer of heat.

OK, locate the legs of the capacitors and turn the circuit board over, find the spot where each leg is soldered on the bottom. Mark with a permanent marker if you like, in case you get going and unsolder all the components :-)

Carefully touch the tip of the iron onto the blob of solder holding one of the legs, at the same time rock the capacitor slightly back and forth with your other hand, with your third hand, try to push the flat screwdriver under the capacitor without scratching the circuit board! This is where I decided to use the adjustable job holder thingo. It can also be done without the screwdriver, but it does make it easier. With some careful levering, not scratching the board, the combination of rocking the capacitor and lightly pushing with the soldering iron, the offending leg should eventually pop free out the side where the capacitor is. Repeat for the other 3 legs.
Try not to overheat the board, the solder just has to be soft/liquified, not boiling.

Brother Knitting Machine Repair 10 - Tinned holes If you have loads of solder on the iron tip, wiping quickly on a piece of paper or slightly damp sponge will remove it. You do want a thin coating of solder on the iron as this transfers heat better to the solder job.

The new capacitors I bought were slightly smaller width ways than the original, but there were extra holes on the circuit board for smaller caps! Fresh solder jobs require “tinning”, this means applying a thin layer of solder onto each surface for ease of joining when the time comes. As you can see, the closer hole is copper coloured eg. no solder on it. Using the soldering iron tip, heat the copper surface and slowly feed the solder wire onto the copper, not the iron. The surface should get hot enough to melt the solder. By heating the job to melt the solder you ensure the solder is making excellent contact with the surface, otherwise the might be floating on the “flux”, the liquid brown stuff that creates the smoke :-) (There is a more technical explaination…)

We also want to make sure the holes are free from solder, just use the tip of the iron and lightly sweep across the holes, removing excess solder from the iron each time, until the hole opens. You do not have to scratch away at the solder with the iron, it will just wipe away when hot, with the iron, don’t touch it with your fingers!

Brother Knitting Machine Repair 11 - Insert Capacitors Insert your new capacitors into the relevant locations (the 0.047uF into C602, 0.1uF into the top spot).

Brother Knitting Machine Repair 12 - Bend Legs Bending the legs outward slightly holds them in position for soldering, do not cut the legs shorter just yet.

Brother Knitting Machine Repair 13 - Solder Solder the legs in place by heating the leg, down near the joint, with the tip of the iron. The capacitors I got were pre-tinned, so I required very little extra solder to make the join.

Brother Knitting Machine Repair 14 - Soldered You may have to feed a little of the solder along the leg (while the iron is making the leg hot) so it creates a small mound up the leg. A good solder joint is pointy like a volcano rather than rounded like half a ball.

Brother Knitting Machine Repair 15 - Trim Legs Give your freshly soldered legs 10 to 30 seconds to cool, then trim them off with some sidecutters. The less sharp leg sticking out, the better, although its not critical.

Brother Knitting Machine Repair 16 - Finished Thats it! Snap your new fuse in and you are finished! Easy! You can now do the reverse of the Disassemble a Knitting Machine to put it back together. I like to test things before they go back together, but if you accidently touch something while the power is plugged in you could be in for a nasty shock, or your family will be… Put it back together first!

I don’t believe it, I fixed a knitting machine!

Once everything is screwed together and plastic rivets are pressed back in, plug it in and turn it on! If more smoke comes out, or it still doesn’t work, start from the top and see if the fuse is blown, there may be something more serious wrong with your knitting machine… sorry about that!

Brother Knitting Machine Repair 17 - Power on

Please feel free to leave a comment or ask a question about the above procedure! Thanks for reading!

19 Comments

  1. tito roque says:

    interesante me gustaria tener el programa por que tengo una maquina igual pero no funciona

  2. Melanne says:

    I have been looking at electronic knitting machine but reluctant to buy. Your artical has eased some of my questions. Thank you for taking the time to write this artical.

    Melanne

  3. lorrwill says:

    Great article, thanks.

    I found a free kh-910 – free because it won’t turn on. I am looking forward to opening it up and seeing what may be lose or blown. That you have written here will be extremely helpful. It has been a few decades since my radio building days!

  4. admin says:

    I hope you get it going!

  5. Churchy says:

    Dear Admin!

    Thank you for your Article. We are a knitting group in Vienna, Austria and we had the same problem. We found your Article after preparing the machine by ourself.

    Best wishes and have a great day!
    Churchy

  6. Anita says:

    Hi
    I cant seem to get a 0.047uF 250V Metallised Polypropylene capacitor
    from anywhere , any idea where i could purchase one from
    Also do i need to replace the two as only the 0.047uF 250V is damaged
    Kind regards
    Anita

  7. admin says:

    Hi Anita,
    The values may differ depending on where you live.
    The place I buy them now calls them 47N for 0.047uF and 100nF for 0.1uF.
    I would advise replacing both. I have done a few of these repairs now and in each one, they have both been damaged. It may only be a matter of time before the other one decides to fail.
    Any electronics store should be able to get them. If you send me your city, state and country (which I will not disclose), I will try to find one close to you. Maybe I should put some kits on eBay :-)
    Hope that helps!

  8. Anita says:

    Hi , Thanks for replying .. Got the parts i needed but its getting someone to replace them for me now :(
    It would be a good idea to put some kits on eBay:)These machine parts are hard to come by
    by the way ,I Love your site Its Very helpful in deed.
    keep up the good work & Thanks once again xxx

  9. Pat Lewis says:

    I have read your article with interest. I have been given a Brother KH-950i and was looking for the power cord to run the computer. I found what looked like the lead with no plug on the end and my husband put an ordinary UK three pin plug on for me to try. It went into the machine and the computer came on for ten seconds before cutting out and a smell of burning came from the lead. Does this machine run on 240volts straight into the wall socket or do we need something to take it down to a lower voltage. Your help would be apreciated before we look into repairing the damage. Thanks Pat

  10. admin says:

    Hello Pat,

    As far as I know, it should be 240v (the ones here in Australia are) so as long as someone didn’t bring it back from the US, it should be 240v… If you follow the instructions above on how to fix it, you should be able to see what values are on the capactiors, eg. the ones I have pictured show 250V and the new ones 275V. I would be pretty confident that they have blown just like all the others I have seen, it seems to be a common problem.

  11. admin says:

    Come on Anita! All you need is a cheap tools like in the list/photo, you can do it! Then you can repair other peoples knitting machines :-)

  12. Maureen says:

    I have managed to get all the parts for my Brother KH950i that has no power like the one you show. If we manage to get power back will this have affected the built in patterns in the computer? Anyone in the UK looking to have a go with your repair will find that Maplins stock the replacements.

  13. admin says:

    The computer should be fine, have not seen one lose its patterns. The effect of these components blowing is really the same as if there was no power cord plugged in. Thanks for the tip for the UK machine knitters!

    Let us know if the repair worked for you. Also, feel free to comment on how my instructions could be changed to make it easier to understand or if they are OK.

    Good luck!

  14. Paula says:

    I own a Brother KH900 knitting machine. I am looking for an adapter to get power to my machine. Please help! Thanks You, Paula

  15. Susan says:

    Hello, I have a 950i that I changed the timing belt on. At the time it would pattern 75% of the time when using the G carriage but not at all when doing anything else. I live in Alaska, so shipping it somewhere will be my last recourse. I thought I got the belt in right but now it will not pattern at all. Does the belt have to fit on the clutch wheel a certain way? All of the needles will move to all positions by hand, but the carraige will not pull any out at all. Please help as I can hardly stand to be without it. Thank you Susie

  16. Zara says:

    Hi,

    I’v just read your article, and hope that you might be able to help with question I have.

    I live in the UK and have a Brother 950i. Next month I will be moving to the US and want to take my knitting machine with me. I could obviously by another one while I’m there, but would love to use my old trusted machine instead!

    I understand that the problem is likely to be to the UK using 240V and in America its 10W. I just wondered whether I could buy an adapter, or perhaps there is an additional lead that you know of, or even some tinkering I could do inside it? Otherwise, I’m sure that the power will blow!

    I’d be grateful for any advise!

    Kind regards,
    Zara

  17. admin says:

    My mother suggests checking out sewing machine type shops also as many have the same power lead. Grab a photo and some measurements of yours and show it around, someone might recognise it! Good luck!

  18. admin says:

    Hi Zara,

    You are correct, UK is 240Volt and the USA uses 110Volt. You should be able to source a “Step Up Transformer”. If you know of any electronics or electrical type shops near you, they would be better to talk to regarding the size you need.

    This link will give you an idea. NOTE: I know nothing about this seller, it’s just an example of what you are after. They seem to be UK based.
    http://www.tlc-direct.co.uk/Main_Index/Transformer_Index/UK_to_USA_Converter/index.html

    Hope that helps!

  19. admin says:

    Hi Susie, Sorry its been so long! I’m afraid you know more about this than me. I have tried to find an answer for you but have nothing. I hope you can find someone to resolve this for you! From the little I know about Alaska, knitted items would be in high demand :-)

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