>
>Should I worry about damaging the output tube?
>
/ If the screen supply is not fused or current limited, applying screen
V without anode V is not good.
>I need to power up this old 5CX3000A pentode amp in a limited way to
>proceed with my checkout. I am nowhere near to applying HV and drive yet,
>but think I have the bias and SG supplies operational and need to check out
>a few voltages and circuits. There is a ton of supporting/protective
>circuitry that I want to observe and try to understand (no schematics).
>
>I am concerned about powering up the main tube because I read warnings
>about operating without plate HV, but perhaps this doesn't apply as long as
>there is no drive.
>
Drive makes no difference. If the anode is mucho positive it is not
sucking up electrons, the electron go for the screen and screen current
is astronomical.
>As far as damage to the big tube is concerned, should I be worried about
>damage to it if I power up all but the drive and HV? I KNOW I have bias on
>grid 1. I am not sure the screen grid actually has voltage until I smoke
>test, because it looks like that circuit is awaiting some relays to pull in
>that probably will in this next step. Any tips/advice/whatever?
>
Screen V and anode V should be there when the grid is biased off.
There's some info and photos of AB1 amps on my Web site.
>cheers,
Jerry
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
- R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
end
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