my wife got me a classic Arduino for Christmas '16, however due to ill health and other problems I've only just got round to assembling it.
I assembled the low-voltage side, no problems. I then assembled the high-voltage circuit but I only have 11.8v at the test points. All components are correctly installed with regards to value and/or polarity - I'm using a 12v regulated supply, and 12v goes into the 740 MOSFET centre pin, but there is no voltage present on the other two. I also tried connecting a tube directly to the HV test points (both polarities) but it didn't switch. All components on the HV side either show 11.8v or 0v.
I have a steady 5.1v at the Arduino socket's pin 1 - would I need to install the Arduino and do a reset or do you think I have a faulty MOSFET or other component?
Thanks for the input, I've been away from home past couple days. I had previously run it with both the Arduino in the socket and out of it. I re-installed the Arduino chip this afternoon, rechecked my soldering and I got an improvement on voltage, but not 170v or higher (it fluctuated between 70 and 100v).
Changed all the components of the HV system one by one until I got a good HV supply. The MOSFET was a bit iffy, once I had changed it, a steady 380v! And better still, nothing gets too hot. Will still heatsink the 7805 and MOSFET anyway, I have plenty of spare aluminium from laptops and computers I have dismantled.
Will post some pictures when I have completed it, just waiting for the tube sockets to arrive now...