Running a Vacuum Cleaner near Tubes

No, it’s fine. The repairman was degaussing which is done to demagnetize equipment. Cathode ray TV’s were prone to becoming excessively magnetic which would pull the electron beam one way or another. Later generation CRT monitors had built in degaussing circuits which ran on turn on.

Mechanical watches sometimes need this too. As far as I know, signal and power tubes are not susceptible to this type of magnetic interference the same way, but I think Luxman has used a degausser for a power transformer in an amp here or there.

It’s most likely the repair person was concerned the strong magnetic motor of a vacuum could magnetize the TV screen again, especially the turn on/turn off magnetic pulses of powerful motors.

Degaussing was also done to erase magnetic tapes in bulk.

Spot on, Erik. I did a stint on TV repair long ago and remember that well. We used to really mess up TVs in the lab by dragging strong magnets across the CRT screen to practice using the degaussing coil to fix the mess.

Thanks guys!  This was extremely informative. There really is a reason and name for what the guy did. For a long time, I’ve been wanting to ask, and I’m glad I did. 

As I am very OCD I would have blown up my tube amps long ago. I vacuum every day. 

I should point out, that while not likely to leave your TV magnetized anymore, motors turning on and off do cause surges in the home.  They claim most surges in a home are from this type of activity, so some amount of noise and surge protection on your delicate electronics is a good idea.  I live near lightning country so I don't run a thing without it.

I've got my system about as isolated as possible while still relying on the grid. It runs on a dedicated 20 amp circuit through a one to one isolation transformer into a line conditioner/voltage regulator before being passed on to my gear. Even with all that, I still kill the power to it during storms. Once bitten, twice shy, and I have yet to be bitten. I'm just anal about protecting my gear. Besides that, tube amps tend to like a nice, refined voltage supply.

BTW toddnlg, I have vivid/fond memories of riding to the local drug store on my bike with a pocket full of tubes to use the tube tester. Somehow, I was the family fixer while my dad was the least mechanically inclined person I have ever met. Hell of a carpenter though. Those were the days!

Man, that TV story brought back some fond memories! We had one of the first sets on our block and many of the neighborhood kids would come over and stare at the test pattern until the Saturday programing began. Our set was about 4 feet high by 3 feet wide with about an 8" screen and an array of wooden knobs, most of which did absolutely nothing. We had to warm it up for about 5 minutes before it would do anything. When things started to go wonky, dad would call the repairman to make a house call. He wore a uniform and had a huge expandable black box with all kind of testers and tubes. If mom knew he was coming, she would vacuum all the dust out back of the TV, probably doing more harm that good.

@rcm1203  I turn off the power when lightning shows up too, but we also have sudden storms here that arrive without much warning and when I'm away, so a Furman surge protection system that is on 24/7 is mandatory for me in addition to the whole-house protector in my panel. 

Electric motors, especially brushed, create RF energy, which you might hear. Older motors surge on start-up, and the starting capacitor can interfere with equipment sometimes. But new motors solve a lot of those old problems, at the cost of not being repairable. Tape heads, mine, at least, benefit from degaussing as well. There is a technique in degaussing tape heads, and a specialist tool. But who listens to tape now a days? Just old fossils.......

I remember when we got a color TV console in the 60's, and the guy had to come by with the Degaussing ring and a mirror to angle in front of the screen, so he could see what all the color adjustment knobs on the back were doing as he was adjusting them. My mom had a rich cousin who bought an RCA color TV when the only thing that was on in color was 'Walt Disney's Wonderful World of Color'.... 

erik_squires  I use the Furman SPR-20i conditioner regulator in my system. Our neighborhood power grid has a bad habit of just blinking off and on for no apparent reason. I have actually found that the protection switch has tripped on it after that happens, so the Furman does do it's job properly. The isolation transformer also helps mitigate the surges that happen when the power blinks. If I am gone on an extended trip, I trip the breaker in the panel. 

@aewarren.  +1

if tube is loose in the socket, it can be sucked in by near-by running vacuum cleaner