#Scope image for krunker blank full#

So, clearly something isn’t right in this last step, given the huge voltage differential between CATHODE and IsolatedGround

#Scope image for krunker blank full#

However when I connect the ‘IsolatedGround’ from the 6.3VDC power supply to the Cathode PIN of the CRT (internally connected on this tube), the power consumption increases and the focus pot gets hot very quickly, taking the a full 600mA load. The step-down power supply works well this way. I have rectified one of the secondary voltage to about +12VDC, then I stepped it down to +6.3VDC regulated. So now I’m thinking to use a +6.3VDC power supply that I had designed on the same board. So I tried several turn ratios and different wire gauges for the 600mA that I need for a 3RP1A CRT but I still cannot hit exactly 6.3VRMS+/-10%. I noticed that even if I’m careful with the winding ratio, it’s difficult to get an exact 6.3VAC under load and the output voltage would also depend on the overall load on the primary, being the regulated secondary winding on the same core (regulated to +250VDC). By now, I have hand-wound my transformer and it has been a somewhat fun experience testing ratios, RMS, checking phase shifts etc. Jörg, thanks so much, now, that transformer is definitely a good find! If I had known a while ago I would have used it.