Francois,? you do NOT require the? 2 x? 50K bleeder? resistors.? ?
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Each of the 8 x 200 uf filter caps already has a 100K resistor across it.? ?2650 vdc / 800k = 3.3 ma?
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The 8 x 100k resistors? serves? ?2 x functions.? (A)? equalizes the voltage drop across each 200uf? electrolytic.? ?(B) provides for some bleeder current...... so when HV shut off, the 2650 vdc? will drop down to 0 Vdc after a few mins.?
When I removed the 2 x 50K @ 50 watt wire wounds (and also the 5K @ 7watt resistor)? ?from the L4PS/ L7PS? HV supply,? the B+ did NOT increase ......remains at 2650 vdc? on RX.??
You won't find bleeder? resistor's being used on any other doubler power supply, none of them.? They all use just a resistor across? each HV electrolytic filter cap.?
Bill Orr's handbook has it wrong.? He shows a single bleeder resistor? ?between? B+ and B-.? ?That will only function as a bleeder resistor.? It will NOT equalize the voltage drops across each HV capacitor.?
And no,? don't insert resistors? ?R1? or RS.? That will make the voltage regulation much worse.? ?That same error is? in some of the older ARRL? hand books.?
In my opinion,? ?we could care less what the B+? is on RX.? ?The real? NO load B+ is what you have when drawing 100 ma idle current.? ?The amplifier has to draw idle current 1st...... before you can apply drive.?
Note, the drake L4PS? and L7PS? HV supplies are identical.? ?I have 4 of the L4PS supplies....and all 4 of then are modified the same way. (I have 4 x drake L4B linear amps).?
The 50k resistor in the CT of the fil xfmr.? It's value is not critical.? ?Anything from 10k? to 100k? will work to cut off the tubes on RX.? ? The dissipation if a 100K resistor? is used? is only .005 watt.? ?Dissipation if 50k ohms is used is? only .01 watt.? ? Dissipation if 10k ohms is used = .050 watt.? ? A 3 watt? MOF resistor is more than ample.? ?NO need for a 25 or 50 watt wire wound as seen in older handbooks.?
Does this make sense now ??
Jim? VE7RF
