Just wondering.
Why did you bypass the supressor? what exactly does that so?
The RF surpessor is a remnant from the past, and stops interferance with analogue TV's and radio's. Not needed in this digital age.
What they DO do, after years of sitting dormant in lofts, garages and other damp places is degrade internally, short out and go pop. Plastic ones, like on old Electrolux's go POP and smell of burning. Metal ones, like on these go KABOOM as they swell alot more. Maybe not today, maybe not this year, but one day, they will go! Electrolux put them in the handle on the 500 series right under your hand, that's fun when that goes, have heard tales from collectors of soiled underwear when they go in use!
Vac 121's tend to slowly melt and trip the house breaker, then stink.
I remove them out of course now, and have had zero ill effects. Even my mums old HIFI on FM isn't affected (turning it up REALLY loud to hear it over the sound of the machine) so I guess it's a very historic thing.