Hmm.
You know the cheap USB PSUs? A transformer that would be small in a 1960s transistor driver stage. The ones that you wonder is the CE mark real? It was a cheap 5V 500mA PSU with Europlug style pins that came with some gadget, I forget which.
I powered the 500mA USB PSU off the lowest HT, centre tap of the two 470 μF caps. I connected the V measure to 0V and the common via a 2.7 MΩ resistor to the 100 kΩ pot across -HT 96V to 0V. The USB PSU started smoking at -46V!
I think a floating PSU with genuine 4 kV isolation is needed. Or an LM3900 based level translator that runs off +12V. That would make it easier to do data capture too.
You know the cheap USB PSUs? A transformer that would be small in a 1960s transistor driver stage. The ones that you wonder is the CE mark real? It was a cheap 5V 500mA PSU with Europlug style pins that came with some gadget, I forget which.
I powered the 500mA USB PSU off the lowest HT, centre tap of the two 470 μF caps. I connected the V measure to 0V and the common via a 2.7 MΩ resistor to the 100 kΩ pot across -HT 96V to 0V. The USB PSU started smoking at -46V!
I think a floating PSU with genuine 4 kV isolation is needed. Or an LM3900 based level translator that runs off +12V. That would make it easier to do data capture too.
