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Author Topic: VAX 121(?) RFI suppressor  (Read 1019 times)

Offline KevinD

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VAX 121(?) RFI suppressor
« on: March 17, 2024, 09:13:23 am »
Morning all,
new to your forum - thanks for letting me join and post. I have a query some of you may be able to help with regarding the sourcing of a new RFI suppressor which I suspect has failed on my very old (~1988) VAX carpet cleaner/vacuum.

I read with interest this thread from some time ago (
I note that the last few posts on that thread talk about sourcing a replacement suppressor, but there are no details of anyone being successful.

I wondered if anyone has subsequently had success in finding a suitable replacement part?

I will give a bit of background to pre-empt a few of the likely questions.....
I think the cleaner is a VAX 121 as it is almost identical to the pics in the excellent series of photos in the above referenced thread, although the solution tank ‘tennis ball’ arrangement is slightly different on mine. I am unsure of the model as most of the lettering from the data plate has faded.
Anyway, the machine started tripping the mains supply RCD after several minutes of use. The time between trips got shorter as the machine warmed up. That happened on both wet and dry. It could be motor insulation failing, but I suspected the most likely cause was the suppressor.
Contacted VAX before I saw your forum, and as predicted by others in your forum on other queries to VAX, they were COMPLETELY useless.
I have bypassed the suppressor, and things seem to run Ok now. I would however like to replace the suppressor if I can as I don’t want to risk the HF ‘noise’ generated by the motor leaking back into my household mains circuit and causing some issues with the various fairly sensitive electronic components we have around houses nowadays (computers, TVs, etc).
Hence this post – if anyone has suggestions or knows where I can get an equivalent RFI suppressor I would be most grateful!

Offline Dyson Tech

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Re: VAX 121(?) RFI suppressor
« Reply #1 on: April 18, 2024, 03:03:59 pm »
Most people do away with supressors altogether nowadays.

Modern electronic devices, such as TVs and computers, are designed with built-in safeguards to mitigate interference from other appliances, including those that may emit electromagnetic noise like older vacuum cleaners.

These devices typically incorporate shielding and filtering mechanisms to ensure proper operation even in environments where electromagnetic interference is present. Additionally, stringent EMC regulations and industry standards require manufacturers to design electronic devices with robust immunity to interference from external sources, including household appliances.

In the context of your situation, where you've observed that bypassing the RFI suppressor in your VAX cleaner hasn't resulted in any adverse effects on your household electronics, it further reinforces the notion that modern devices are generally well-equipped to handle such interference.
We expect that by seeking advice here, you are competent enough to be able to make any electrical installations safely and in a safe and legal manner in your jurisdiction. If you are in any doubt whatsoever, do consult an electrician. You implement any advice you read at this site at your own risk.

Offline KevinD

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Re: VAX 121(?) RFI suppressor
« Reply #2 on: April 19, 2024, 08:36:42 am »
Hello Dyson Tech,
thanks for the reply. OK, hear what you are saying, and I bow to your greater experience here, so I will stop worrying about it and continue to use my ~ 35 year old carpet washer/vacuum cleaner as it is.
If only we still made such robust items nowadays.



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