Sewing machine query - capacitor requirements

[Mrs Twosheds]

Hi guys. Any advice greatly appreciated, please.

I have a 1970 Bernina sewing machine. It works a treat, but has just popped loudly and emitted a puff of smoke. I gather that the motor suppressor/capacitor gives up the ghost on these old machines as a regular thing. Sadly, Bernina don’t make the part any longer. Opinion seems to be divided as to whether to carry on using it without this part, or whether it’s unsafe/potentially damaging to the machine. There are supposed ‘replacement’ parts on eBay, but these have only 2 wires and the original has 4 (a double unit?).

I’ve found mention of the part, which claims it requires: 1x0.02 uFx2. 1x0.06 uFx2. 2x 2000 pF Y2. 1x2.2M (followed by a symbol resembling a horseshoe). I have no idea what this means. Can it be substituted with anything else I can buy? Is it safe to use?
Huge thanks so much for any help you can offer.

 

[Mrs Twosheds]

Thank you so much, Marvo. That’s a really interesting idea - I’ll look into that, too!

 

[Avo Mk8]

I would replace it with a noise filter board you can scavenge from an old microwave or washing machine. If you're not in a scavenging mood they're also available as new items from Amazon or EBay although I'd strongly recommend buying an OEM version and not a cheap Chinese knockoff. It will arrive as a bare PCB so obviously you'd need to put it into a small profect box. They look something like this;

View attachment 116750

I honestly think this is not a practical way to go.
There's no wiring or access to power in the body of the sewing machine, it's all in the (separate) motor housing as far as I'm aware, and there is very limited space. Given you can buy an encapsulated X & Y capacitor/resistor module of the right type that would drop in, the delta filter I linked to would be a much easier fix.
Also the example you show doesn't seem to have the capacitors needed to quench the arcing of the brushes of the motor, so probably wouldn't do the job!

Just to illustrate the space available, this is where the suppressor needs to go (or equivalent for the machine in question)

 

[Marvo]

Yeah, the safety and aesthetics would need to be assessed by the person installing it and my suggestion may not be a practical solution depending on the layout of the existing setup. Looking at the component values in the first post I summized it to be noise suppression filter rather than a brush arc suppression snubber but I could of course be wrong. With old brush motors most of the brush arc suppression was mitigated by the brujshes being resistive and they were notorious for developing excessive arcing when generic replacement brushes were fitted which often were of the same form factor but a different resistance to the OEM brushes. Brush motors of that era used to generate large amounts of noise that was especially unwanted because the medium wave radios in everyones kitchen andv lounge were very prone to picking it up. The components listed look to me like noise suppression and the generic filter board I suggested should suffice on a technical level for that purpose although maybe not on a logistical one.