5FP7 project starting with the focusing coil.

[AdrianPH]

For some reason in my mind I had discounted push pull, I think because of the flyback pulse, I was relying on that to get the spot to the left hand side of the screen and I am unsure of what a push pull stage would do, or how the pulses in both triodes would effect the spot etc.  But it is something I can certainly try, I am assuming biasing the valves near cut off??

Also please do not think I am trying to prove you wrong or disagreeing with what you are saying to me, you are obviously way more technical/knowledgable in this field than myself.  But I have always found it hard to just take things as read or believe what I am told without it being shown to me in a practical way.  I was a repair engineer, for 40 years, I did not have to understand how a circuit worked, just how to find a faulty component, in fact the bosses did not want highly technical staff, they would have to pay a lot more! So I have to rely on trying something, if it does not work dig into it until it makes sense.

I am still finding it difficult to see why you are saying voltage is the driving factor, this is because I see valves as a current source, so if I bias a valve to give 10mA it cares not if the voltage on it's anode is 100 or 200 volts, or if the load resistance is 500 or 5K ohms within reason.  I can understand if the  transformer was on the mains supply or some really low impedance source at 12.5 Hz then the current would be just limited by the resistance of the windings.  lastly I am past the 60 mark the grey matter is not as quick to understand unknown territory so please do bear with me.


Adrian