11-11-2016, 08:35 PM
Nope did not guess it 
Plus have none in the basement and cannot make the whole family to stop using computers or watching TV.
FOUND IT!
While checking the grounding bolts on backelite block and measuring them to GND I found missing connection in the backelite holding the Y-caps of the MAINS filter. The reason: they used this for the solder post to bring one of the power wires in and connect to the power transformer. The post has insulating base effectively isolating the bolt from the block's power lug, so the 10nF caps have no center GND point.
After that the hum went WAY down. A little remains but no worse than the rest of my radios. And this is when plugged through the isolation transformer; when plugged into the outlet straight, no hum.
Terry, remember the discussion about these caps one day here? Well....they do matter
Plus have none in the basement and cannot make the whole family to stop using computers or watching TV.
FOUND IT!
While checking the grounding bolts on backelite block and measuring them to GND I found missing connection in the backelite holding the Y-caps of the MAINS filter. The reason: they used this for the solder post to bring one of the power wires in and connect to the power transformer. The post has insulating base effectively isolating the bolt from the block's power lug, so the 10nF caps have no center GND point.
After that the hum went WAY down. A little remains but no worse than the rest of my radios. And this is when plugged through the isolation transformer; when plugged into the outlet straight, no hum.
Terry, remember the discussion about these caps one day here? Well....they do matter
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
