[TenTec] Station power supply??

[Jim Brown]

On 9/5/2012 11:45 AM, Richards wrote:
>
>
>     Is this notion of bonding the V- to chassis in any way
>     related one could get shocked when touching the
>     chassis of an old Halicrafters tube sets?

NO. But it IS caused when the GREEN WIRE is not properly bonded to the 
chassis, or when every chassis is not bonded to every other chassis and 
to ground. That GREEN WIRE IS GROUND, coming all the way from the 
breaker panel that feeds it. It's not a great RF ground, but it's a 
great SAFETY ground, and it is required by LAW in virtually every 
developed country. .

>
>
> Observation:
>
> [I am still taking Electronics 101.   But I remember the
> time I got stung touching a hot chassis.}
>
> I would have thought a serious concept like grounding stuff would be 
> so important, it would be codified in a consistent set of rules even 
> rookie operators could apply and follow.

It is, that "codification is the National Electric Code (NEC), and there 
is excellent material on this in recent editions of the ARRL Handbook.

> Also, I would have thought the product manufacturers would be on one 
> track, with consistent instructions and consistency in the gear.

The Astrons are DESIGNED correctly, but the PAINT is a manufacturing 
defect.

>
> But... NOOooo...  that would be too easy!   Consider, f'rinstance, 
> this topic of grounding power supply chassis.   Nearly every rig needs 
> a power supply.   Nearly every instruction manual says to ground each 
> chassis to the other ones, and to a stick in the mud. Even TenTec says 
> to do that in my transceiver user manual.
>
> OK... but then there is no ground lug on my TT 963 power supply. There 
> is no ground lug on 2 of my Astron power supplies.

Well, there is, it's called the GREEN WIRE.

> There is no ground lug on my TT receiver, and similarly no ground lug 
> on most of of my station accessories.  And yet they all have AC or DC 
> power.

That's unusual. Most ham rigs I've seen have a ground lug.

> Some guys say to wire the green wire to the chassis (which I somehow 
> get)  but then other guys debate wiring the negative to chassis (which 
> I don't get, because I remember the sting of my old radio years ago). 
> Some advocate adding a ground lug to the power supply chassis - but 
> the manufacturer did not.
>
> And then TenTec service told me not to ground ANY of it unless I have 
> a specific problem to solve, which just a little contradicts what it 
> says in the instruction manual.  Some guys have grounding bars across 
> the back of their desks.  Others don't have anything. One would have 
> thought, if all these things are supposed to work together, there 
> would be a common way of doing it.

That's why it's important to develop an effective BS filter.  One of the 
best BS filters is EDUCATION.  You're an attorney, as I recall, so I'll 
bet you've got a pretty good BS filter in that field, and to some extent 
with respect human nature and reading people. But until you develop your 
technical BS filter (see education, above) you're always going to be 
wondering who to believe.

> Heck, now you guys say even Astron is inconsistent over time - and on 
> the same model supply, too.   And now we are all wrangling over 
> different rules and approaches to it.

The only RULES here are that, BY LAW, EVERY exposed chassis MUST be 
bonded to ground, if it's connected to the power line, it MUST be bonded 
to the Green Wire, and ALL grounds MUST BE bonded together. And for good 
RF performance, and to minimize hum and buzz, those bonds should be 
short fat copper.

FWIW, I've written extensively about all of this stuff in tutorials that 
are on my website.  All you have to do is study them.

73, Jim K9YC