[Hallicrafters] AC Bypass Caps in SX-111 MK 1.

[Peter Bertini]

You'll have 60 VAC regardless, the two caps across the line to the chassis
form a voltage divider. Caps are normally limited to .015uF max. to limit
the reactive currents.

If you do put them in, a three wire power cord with a ground return is a
must; and only use UL rated linebypass safety caps. Without the chassis
being grounded you'll get nipped everytime you get between the chassis and
earth ground.

Pete

On Sun, Dec 12, 2010 at 11:39 PM, Mike Everette <radiocompass at yahoo.com>wrote:

> Mark,
>
> I'm sure some folks will disagree with me... but I would recommend that you
> not
> sweat those line bypass caps.  In fact, LEAVE THEM THE HECK OUT.
>
> If they start to leak much at all, you are going to have AC voltage on the
> chassis.  I've seen radios with between 30 and 60 volts AC on them for this
> reason.  That's enough to give you one serious jolt.  And yes, this was due
> to
> line bypass capacitor leakage... not leakage in the power transformer.  In
> all
> my experience,  which includes ham radio, commercial two-way, avionics, and
> broadcast engineering, I have seen only two power transformers develop
> primary-to-frame leakage; but PLENTY of leaky line bypass caps.  I damn
> near got
> killed once by a background-music system PA amplifier with a hot chassis
> from a
> leaky cap, when the back of my head touched that chassi as I was reaching
> my
> bare and sweaty arm behind a HVAC duct to fish out a speaker lead.
> Sha-ZAAAAAAM!  As a result, the very first thing I do when a "new" radio or
> any
> other device comes into my life is to make REAL sure to take the things out
> of
> it!
>
> I remain unconvinced regarding the benefits of having these capacitors in
> the
> radio at all.... except to a funeral director.
>
> 73
>
> Mike
> W4DSE
>
>
>
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