Doesn't it depend on how you define 'standby'?
I use the following logical states in my amp:
OFF - as it says
ON - in the warming up period, not available for use
STANDBY - ready to go but no HV, bias or screen volts applied
RECEIVE - all voltages on, antenna and send/receive relays in receive state
OPERATE - producing power
but that's just a personal approach. In cases where PIN diodes are used in the
in/out RF switches, you may well need an appreciable voltage in 'non-operating'
conditions to allow the amp to be in bypass mode.
My rule is that you don't power it up without covers until you've looked at the
instruction book and circuit, you NEVER use both hands to apply probes when
power is on, and always use a clip lead to ground the HV line when you've
killed the power and are going inside. (This has problems - a number of times
I've forgotten to remove the clip lead! Still, saves other problems)
Personally, I find the biggest danger is that I get used to working on stuff
with 24 volts or less, and I forget, especially with the 200-300 volt lines,
that they are dangerous.
73
Peter G3RZP
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