userx2
Full Member level 3
Hello,
I am repairing a high voltage arc starting circuit on a PCB for a TIG welding machine.
It uses a HF oscillator with step up transformer and several voltage doubler stages made from diodes and capacitors.
All of it is thru hole stuff.
The problem is that the voltage multiplier circuit is fried because there was arcing from the final output resistor back to a capacitor in the multiplier chain.
This is because the PCB design is not good and the gaps between the physical components are inadequate. That resistor being very close to those other parts.
It arced straight through the resistor body insulation, through the air and into the blue disk capacitor next to it, also through its insulation.
I can't change that design but I am hoping to prevent this problem from re-occurring by means of some suitable barrier between these parts.
Without spending any more $ what could I use for this purpose?
BTW, 10x 1nF Y1 capacitors, 4 resistors and 8x 4kV diodes cost me US$54 at Dig Key. I cannot believe how expensive components have recently become!!
Regards
X
I am repairing a high voltage arc starting circuit on a PCB for a TIG welding machine.
It uses a HF oscillator with step up transformer and several voltage doubler stages made from diodes and capacitors.
All of it is thru hole stuff.
The problem is that the voltage multiplier circuit is fried because there was arcing from the final output resistor back to a capacitor in the multiplier chain.
This is because the PCB design is not good and the gaps between the physical components are inadequate. That resistor being very close to those other parts.
It arced straight through the resistor body insulation, through the air and into the blue disk capacitor next to it, also through its insulation.
I can't change that design but I am hoping to prevent this problem from re-occurring by means of some suitable barrier between these parts.
Without spending any more $ what could I use for this purpose?
BTW, 10x 1nF Y1 capacitors, 4 resistors and 8x 4kV diodes cost me US$54 at Dig Key. I cannot believe how expensive components have recently become!!
Regards
X