Jeroni Paul wrote:
Chuck wrote:
In a similar vein to your remote story, we sold an $1800 Tandberg
cassette deck that came to the shop over and over again for not
responding to the transport keys. In the shop it always worked
perfectly. I decided to go to the customer's house after work to see
what the problem was. At his house, the keys didn't work. I spotted
a light dimmer on the wall. Turning it off and the deck worked
perfectly.


I have a SABA music system (radio + cassette + turntable + audio in/out plugs + remote control), time ago I had it connected to a desktop PC to play music from the PC. One day the printer attached to the same PC was taken out for repair due to clogged heads.

The next day I found the SABA turned on with the MUTE activated (the radio was selected so the FM display etc was all lit, but no sound). Since I never used to use the MUTE button and I was the only one at home to use that thing I was quite surprised. I unmuted it and turned it off, all appeared to work correctly. The same day in the evening the same again, that made it obvious it was not me. In the next few days the same kept happening at random times but never when I was there, and because it would turn on with the mute set I could not hear when it happened.

Finally one day it was off, I went to the kitchen and when I came back it was on and muted again, so I guessed a relation had to exist. Turned it off and went to the kitchen again - no joy. Repeated a few times and surprise - again on and muted. Some more experiments revealed that switching off the kitchen light sometimes would cause the SABA to turn on and activate the mute at the same time.

The kitchen light consists of two 36W fluorescent tubes, apparently the inductive kick at turn off found its way into the SABA digital controls. They were two rooms apart, so not exactly next to the kitchen switch or lights. The issue did not reoccur after I plugged the printer back.

Ha!

Was noise filtering on the always on printer was somehow supressing the
interference?