Fixing the capacitor on my Bernina 930 

It says 0.01 microfarad 250 volts on the side Microfarads use the mu symbol so sometimes it is easier to search for this capacitor as 10 nanofarads or nF Hope that helps

I can remember changing the needle stop by mistake and being very confused about what I had changed. It was up by the hand wheel I think? But I was checking in the foot pedal for a setting my machine doesn't have. Very frustrating at the time

@@Dav4122 This needle stop function also got me puzzled. Now I decided to make a video about it: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KlTcVkgD2Hk.html

I think I tried tweezers, a chopstick, and then both to get it to click back into place

Thanks for your quick answer. I just found out that you can remove the lamp module easily with 2 screws. Then you have sufficient space to approach the pen with the spring clip.

Manualslib.com it's the "service guide model 930" I remember there being several competing versions, I used the "sewing educational warehouse" version. Hope that helps

Thank you yes it will help

Following.

When my capacitor blew it was stopping the current flowing so my machine didn't run until I fixed it. I'm not sure what specifically wasn't getting power though other than it was essential. If yours still runs then the current is still able to flow but won't be benefiting from the capacitor evening out any highs or lows in voltage, so less safe from further electrical damage. I would fix it if you can, but it's your choice.

@@Dav4122 thank you.. I have ordered a new one.

@@Dav4122 Thanks for the info. This is Scott, her husband. I am away from the machine and trying to help diagnose it remotely. Do you think that cap is a motor start capacitor? Sounds like maybe so, since yours stopped running. But hers still runs. So I don't fully understand the function of this capacitor. Weird.

Just read all the comments to @Horse Nuts, He said "These are just interference supression capacitors. They're only necessary if you have an old CRT TV that you watch in close proximity to the sewing machine, or if you listen to AM radio. Most of the time, you can just cut them out and the machine will work perfectly well without them.

I've had a look at a photo I took of which bolts go where There are two more spots that I undid bolts from The lower left has a silver heatsink/fin and it's bolt goes through the fin and PCB into the case There are three bolts on the black plastic magnet/relay cover that go all the way through to the case as well (the middle one is much longer so start with it and you may not need to do the other two) Hope that helps, I can always open the back of mine and take another look if you need me to :)

David Hansen Brilliant! I started loosening the middle screw in the black plastic magnet & the board just came away. Thank you so much. I’ve order a new capacitor from the UK, so I’ve just got to get my Dad’s soldering iron (exact same one as yours!) & practise (never used one before). One other question, how did you get that spring clip back in - I used a pair of angled tweezers to get it out. Thank you once again. Suzy

I didn't think to try just bridging the two points with a wire, probably because I could source a direct replacement. Thanks for the insight on what that capacitors use may have been.

@@Dav4122 Nope, don't ever short it out with wire - that would be a very bad idea indeed (the motor would probably run at full speed). Just remove the old capacitor, and throw it in the bin. Job done! Capacitors don't have a direct electrical connection between the two contacts - there is a microscopic air gap between the plates, and that is what provides the smoothing to prevent radio interference. They are only needed to prevent 'snow' on your old 1970s TV screen if you have an analogue TV aerial, or complaints from granny if she is listening to her shortwave radio. Digital technology is immune to the sort of interference that sewing machine motors might produce. Hence, in 2022, these old supressing capacitors can simply be cut out and discarded. Indeed, it is probably the first thing one should do with an old sewing machine in order to prevent the awful smell should an old capacitor decide to burn itself out.

@@horsenuts1831 so my machine is working fine with the blown capacitor still in it. Is it okay to leave it in and use it? Or should I remove it?

There were some visible screws and some cables I needed to undo I think I undid one on the transformer that I didn't need to but did just in case. If you are careful and pay attention to where things are sticking you will have no issues

The transformer is 240v ac to about 19v ac

@@Dav4122 I am working on this same machine and I am having a very odd problem. the machine powers up no problem, press the foot pedal machine runs just fine but as soon as I release the pedal it continues running non stop. I have check the L PCB and sure enough it has the same capacitor your that your replaced blown. question what impact does this capacitor have on the operation of the machine allowing it to run non stop the only way to get it to stop is pulling the power cord. Do you have the specs on the capacitor for a 110v machine. thanks SImon

If you search for "Bernina 930 capacitor" you should get an ebay link 0.1uF, 100nF 275Vac class X2 capacitor

@@Dav4122 I'd like to add that in my 930 I had a Rifa 100nF 250VAC X PME271 M610 capacitor. Slight difference but still.

Manualslib.com it's the "service guide model 930" I used the "sewing educational warehouse" version which has some color pictures rather than all black and white