In article , Don Pearce
wrote:


Just one thing to remember. When working on live valve circuits, keep
one hand in the pocket at all times.

You beat me to that. :-)

I'd add: make sure the mains switch on the wall is within easy reach. There
will be times when you wish to switch off the unit in front of you with
minimal delay. :-)

Also, "do not poke components with a pencil".

Crepe-soled shoes are a help, too. (I know, that's two things). I found
all that out the hard way in my early days of design.

One of my ex-colleagues used to work on HV discharge lasers 'live' whilst
wearing rubber boots. Mind you, he was a bit crazy. Doubt the
health-and-safety people would let you do it now.

I have always been much more slow-and-cowardly. If kit has mains, or above
about 50Vdc I am inclined to keep shutting everything down when I want to
move probes about, etc. Slower. But you get time to think about what comes
next, and may live longer to do more thinking. :-) Also checks out that
the kit can be turned on and off a lot without problems.

I also tend to prefer bench supplies when developing or testing an amp, and
only connect to the working PSU when doing more protracted tests. Bench
supplies give more safety options, and can also be useful for checking
other effects, etc.

Hence my other advice tends to be "pause and think again, and try to work
out what devious ways the kit in front of your has just devised to try and
kill you." This is also what tea breaks are for.

Just one more thing - don't hit the 500VDC supply with a spanner while
hanging onto the metal rack with the other hand. You travel a long way,
and you don't find the spanner again.

My personal estimate is that about 2kV equals about one rotation of the
human body and you bowl over backwards (if lucky). This is roughly what I
did one day courtesy of someone else rewiring a klystron without telling
me.

Slainte,

Jim

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