A not so gentle reminder - HV is unforgiving

[Steve Harrison]

At 12:47 AM 11/27/98 -0500, David Humbertson wrote:

>...Spent most of the day putting the finishing touches on a very
>nice SB-200 I just picked up - had put the top shield on and
>just had it on the bench "burning in" this evening as my family
>and I had our Thanksgiving dinner etc. I went downstairs to my
>BA bench to give it a look and for some reason I put my right hand
>on the right side, feeling for heat from the bleeder resistors safely
>inside. My little finger must have curled under a bit and what
>happened next is just a blur as it came in contact with the 2400
>volt runner on the outside edge of the PS board -

.... apparently, you left it running, UNATTENDED, on the bench, WITHOUT THE
COVER??!!

I don't know how many there are in your family; their ages (small, curious
ones, perhaps?), or whether you have any pets; but the only time I would
think it permissible to leave a HV PS running in the open like that while
completely unattended is...

NEVER!!! Under ANY circumstances! PARTICULARLY with no safety shields in
place!

What if something happened to you at the dinner table: the knife slipped,
or you collapsed, and you wound up incapacitated; how would any family
member or emergency squad personnel know what to do about whatever you may
have left running? How would ANY of them even know that amplifier was
super-dangerous to the unknowing? In their rush to turn it off, they might
lean over it to pull the plug from the wall, even after hitting the ON/OFF
switch. Feeling the heat radiating from it, they might even try to handle
it to see whether there was danger of a fire somewhere. BEFORE the HV bled
down, not knowing anything about slow discharge of HV power supplies. With
BOTH hands.

What if something had begun arcing, spitting little balls of molten metal
all over the workbench while you were gone, starting a fire... on
Thanksgiving Day, yet.

No, I just can't conceive of a circumstance that would warrant the terrible
risk of leaving something like that running, especially with others in the
house who might have no idea whatsoever how to handle the equipment.

We're all glad that you related this story to us, Dave... we know it was
painful (in more ways than one). Hopefully, the rest of us will now begin
to think a bit deeper, and a bit further ahead, about what we're doing when
we're working on our BAs. No doubt about it: these BAs can represent a
life-threatening danger to many of today's generation who are unaccustomed
to tube equipment with their necessary high voltage power supplies, not
just to folks like ourselves who love and work on it with such familiarity
and abandon.

By choosing to "play" with BAs, I think we have all unwittingly taken on a
new responsibility that, because of the equipment age and thus unfamiliar
technology to today's generation, we may have never considered before: this
equipment can present unfamiliar dangers to many others, whether within or
outside our own families, whether emergency personnel or the curious. We
should try to keep that in mind at all times; and by doing so, we will only
make our own actions safer to ourselves, too.

73, Steve Ko0U/1

P.S. Yes, I've had my own jolt: I was thrown clear across my bedroom some
30 years ago while I was playing INSIDE my 4-1000 amplifier. Hasn't
happened since so I guess I'm due for another "reminder"...

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