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Yes. Very true but I' had it where the tubes will flashover at 1900/2000V, so by changing the HV output wires on amps like the AL-80B and TL-922, you can easily get to around 1000V to start the

He can also just use the low 1900 vdc CW position, apply a bit of drive, and tune the amp a bit off resonance.? ?That will get the tubes good and red. A good Eimac 3-500Z? will? hi-pot? 16 kv?

Francois...... Eimac and the other makers of the 3-500Z? used this chemical, called? 'Zirconium'? ?on the anodes.? ?The Zirconium coated anode IS the getter.? It is heat activated when the tube

Hi Francois. Running the tubes on filament only does not help at all. You must apply drive to activate the gettering process. See https://www.w8ji.com/gettering_tubes_al572b_al80b.htm That is a

Thank you for this very important information. The PA has not been used for 10 years. So there is no point in heating the filaments for only 1 or 2 days to hope to degas. I need to heat the

If you run 500W PEP only, your tubes will quickly become gassy. They have no separate getters. The gettering is done by the anodes and so they must become red during operation to keep them

Thank you for your patience As for the resistors at the terminals of the filter capacitors, I understood that they allowed to distribute the voltage at the terminal of each capacitor fairly. It is

Francois,? you do NOT require the? 2 x? 50K bleeder? resistors. Each of the 8 x 200 uf filter caps already has a 100K resistor across it.? ?2650 vdc / 800k = 3.3 ma The 8 x 100k resistors?

Hello Thanks for the dictionary; it was essential. Fortunately I made a diagram so that you could tell me that it was not the right solution. I now have to translate your text to make a

Dentron Clipperton L and Yaesu FL-2100B have no grid current metering, so B- is chassis ground. I just did the hard grounding of grids on my FL-2100B. cathode goes through bias diodes to ground with

You can either float the supply, OR grnd the B+.... OR grnd the B-.? ? If you grnd the B+ to the chassis.... you now have a -5kv supply...which will also kill u.? ?This assumes the safety diodes

You still have it wrong.? ?The 2 x 50K? @ 50 watt? wire wound resistors in the L7PS are removed.? ?The 5K @ 7 watt resistor below the chassis? of the L7PS is also removed. (Originally, Drake

HV =? h

Along the same lines as I mentioned the other day, QRO Technology made a blunder on the HF 2500 amplifier. ?I found this problem when a local ham called me and told me that his HF 2500 would restart

I have drawn a simplified diagram of the L-7 power supply. I have drawn in red an additional bridge to establish to prevent the cathode from being isolated. In emission, the ammeter is

Hi fellas Sounds like you guys learned in your hobby what I used to teach my junior electrical engineers. Of course, they all worried about the hot wire. I told them in order of importance, it’s

Hello Your participation is very interesting because I am in the process of putting a Drake L-7 back into service. I understand very well the electrical problem that you mention and the original

Lou can chime in on this one.? On? the..... "big 3"? ? ameritron amps....... they don't use a resistor at all.? On RX it's wide open !? ?I got into an argument with W8JI about this years ago.?

Low mu triodes are useless for GG.? ?Reason is...... they require a stupid high amount of bias V? to obtain normal idle current.? ?You can see that effect asap, by looking at the constant current

Hi Everyone, I thought I might find a bad tube by swapping both tubes in and out one at a time.?? Only thing I confirmed is that what ever the problem is, it hasn't healed itself.?? FWIW I checked