Do you know this... Capacitor?

[tcm]

So in an obviously completely unrelated, definitely nothing to do with me taking apart the speed controller, subject can anyone suggest a good modern replacement for this capacitor?
It's about 20mm square.

Capacitor.jpg (366.73 KiB) Viewed 666 times

[aeromech3]

Looks very much like the one in your first pictures on this thread. Had a look inside my Necchi controller and there is a radial 0,1uF 250V~ Safety Capacitor across the inputs; unfortunately a search of its source leads to USA. B81121-C-E12. which is MKC 0,1uF (X) 250V~.
Nearest I have seen, but you could ask Farnell or RS for advice too.

[tcm]

I've already mentioned this at the tail end of another topic so apologies if it's not new to you but I thought it maybe made more sense as it's own question.

I recently managed to snap the lead off a vintage capacitor and am hoping someone can tell me what would be a suitable modern replacement.

It's labelled 02 and so far suggestions have been 0.02uF, 2uF and 0.02pF (which seems unlikely to me).

It goes across positive and negative on a sewing machines speed controller.

At the moment I'm leaning towards a 0.022uF X2 suppression capacitor but would dearly love any advice.

Thanks, Tony

Capacitor.jpg (366.73 KiB) Viewed 637 times

[Retired]

Hi,

You could get the capacitor tested easily if you know someone with a tester.

If not then you could repair it. I spent ten years restoring vintage radios starting from scratch; it quickly became clear I needed three hands; one for holding the soldering iron; one for holding the solder and another for holding the component to be soldered. To overcome this problem I dreamt up a mini wire coil winder;

Winders 1.JPG (100.82 KiB) Viewed 573 times

I made quite a few of these mini coil winders as presents and many were copied.

Mini coils 2_0001.JPG (69.67 KiB) Viewed 573 times

I added a mini coil to each end of a component such as resistor or capacitor; the idea was to snip out the faulty component but to leave a short tail of about 1/4" which meant I didn't lose position where to solder in the new component; I would scrape the tails clean; add the coils then I could simply slip the new components into place allowing both hands to solder; it worked so well I had an article published and as I say many were copied.

The picture you added of the broken capacitor shows it to have a short tail; clean this tail then add a couple of turns onto the broken wire and slip it on then quickly solder but don't overheat the capacitor and then all should be well; sorry I can't identify the capacitor from the information supplied because I've replaced hundreds of these but at lots of various capacitance's.

Could you browse online for a circuit diagram which might also help?

Kind regards, Col.

[tcm]

Thank you both very much for getting back to me.

I had thought about testing the capacitor but don't know anyone with a tester. I even considered getting a tester but have been trying to follow Adam Savage's (of Mythbusters) rule of not getting something unless you have good reason to think you'll use it at least three times over the next year.

I like your mini coil winder Colin, it looks very handy.
I've fancied a decent 'third hand' for quite some time but can't really justify the money or space for something that wouldn't be used that regularly. For the time being I make do with one of those cheap crocodile clip things.

The capacitor tail had snapped off right at the body of the capacitor but I scraped it back slightly in the hope that I might be able to expose enough to attempt a repair.
Sadly to see enough to solder to I realised it had exposed the plate which I figured wasn't a good idea although I did briefly consider soldering a new tail and then covering the edge with a little resin but decided the repair was sounding ever more ridiculous.

I did some more research and the oldest capacitor code I could find suggested it would be 02pF but I also found that other similar (although not the same) pedals almost all used a 0.1uF capacitor (as with aeromech3's controller). From what I've seen around 0.1uF would seem far more usual as a suppression capacitor than 02pF but take that with a large pinch of salt as I readily admit I know very little on the subject.
By chance I happen to have a 0.1uF capacitor in one of my many 'useful one day' boxes so my current plan is to use that.

Please feel free to make any other recommendations / corrections.

Thanks again for the help, Tony

[aeromech3]

And you do realise that any old capacitor is not good enough, the safety capacitor (designated by X ) is best used when bridging across the poles.

[tcm]

And you do realise that any old capacitor is not good enough, the safety capacitor (designated by X ) is best used when bridging across the poles.

Yes, thanks for pointing that out. I have a 0.1uF X2 capacitor ready to go. It's only rated to 250V so could be better but should do.

I always prefer to have these things pointed out as I know I have an awful lot to learn on the subject.