Capacitor for vintage Kenwood Mixer

[Brad1980]

Hello. I have just stumbled across this excellent forum while looking for a replacement capacitor.

We have a Kenwood A700 food mixer which was manufactured in the UK around 1951. Unfortunately one of the capacitors has failed and needs replaced. It is a Dubilier (paper dielectric) type 4700B, 0.1 Microfarad +/- 20% 500V DC WKG 71 Deg C. I managed to find an old catalogue dated 1951 (see link below) and it appears on page 12. Unfortunately the dimensions are not the same. (38mm long rather than 2 1/8 inches and 16mm in diameter rather than 1/2 inch).

My questions are where can I purchase a replacement part of the correct specification? Is there a modern equivalent available that might fit?

I hope I have provided sufficient info.


https://ethw.org/w/images/d/de/Dubil...Capacitors.pdf

[GMB]

The slightly later model used X-class capacitors, but these are rectangular with leads for PCB mounting. Given the application I think you would ideally fit a modern X-class but they will be a different shape so it might be a problem.

If you want something of the same shape as before then most axial modern capacitors will be smaller. I would go for a 1kV DC rating but check it is good for mains a/c. (X-class are designed for that use).

Does the older model have 2 capacitors? If so I would change them both. On the later model, one is for supression and the other is part of the firing circuit for the triac.

[Herald1360]

Any axial leaded polypropylene 100nF 630V or 1000V capacitor that will fit will do.

Something like this:

https://www.ebay.co.uk/itm/Axial-Pol...edirect=mobile

[Brad1980]

Thanks for the quick response. It gives me something to work on

[dglcomp]

I suppose would using a modern X rated part (i.e. https://uk.rs-online.com/web/p/polyp...itors/7398629/ )and getting around the size problem by using a bit of "choc-block" and a couple of short lengths of wire be the best solution, also saves having to use NOS parts.

In my opinion using a modern part to repair a bit of vintage kit in use is fine, adds to the history of it. Always handy to leave a note inside for future reference.

[Uncle Bulgaria]

Don't worry - it's a straightforward repair, and modern components are smaller and more reliable. There's even a UK company that specialises in restoring Kenwood Chefs. They do a motor repair kit for some different models, one of which is the A700D. Perhaps similar to yours?

A700D Motor Repair Kit

I have used them before when I needed new motor brushes for my A901. I also replaced a tired suppression electrolytic with a new X class box capacitor. I didn't have a problem fitting it in, but there may be a requirement for a certain sized part for an A700, though the kit linked above appears to show a normal poly capacitor.

At the bottom of this page on capacitors commonly found in radios, you'll see illustrations of the most common modern types. The first yellow axial one similar to Herald1360's link would be suitable for you, for example.

It's probably cheaper for you to get your new capacitor from a Bulgarian supplier, especially with Brexit, and one of the options from the other members here will surely be available near you.

Oh, and congratulations on your sleuthing work to find that catalogue!

[PaulR]

I have used that repair kit and it works well. The resistor is difficult to fit into the case, though. If it is just the capacitor that has failed on yours I would be tempted to keep the rest original and just do the capacitor(s) Lots of oily, greasy fun to be had!!

[Uncle Bulgaria]

Oh yes, lots of that in the gearbox!

[John_BS]

The 1950's A700 employed Tufnol gears, presumably for noise / self-lube reasons.

John

[PaulR]

So, do the Tufnol geared ones not have that horrible grease packing?

As far as I know only the big gear is Tufnol, small ones steel and have lubrication. Grease packing isn't horrible but rather necessary for lubrication, much easier to make a grease proof (and fillable) container compared to oil.

[John_BS]

I think I know what Paul means: there was a lot of it, and it would seperate itself from the gear-train. My father used to delve in every few years to push it back into the "working" area. The oil started to seperate out after a couple of decades, so the paint below the gasket level would start to look yellow.

John

[Brad1980]

Some great and interesting replies there. Going into town in the next few days to see what I can find. Should be a fine challenge for my stumbling Bulgarian. Cheers for now!

[kirstyd]

just done the caps and the big resistor in ours .i bought one of those kits from eBay .the machine would only run at high speed .its working perfectly now .Also stripped the gearbox cleaned it and filled it with new grease [its a lot quieter now] .Thought i might as well spray the metal body while i was at it .The machine now works like new and looks like it did 55 years ago when it was new

[PaulR]

Like so many household appliances of that era they seem to be made to last for ever and be repairable.