[time-nuts] 58517A external SMC power versus PORT1 power (was Re: HP Z3801A on eBay -- And check this out as)

[Christopher Hoover]

> Well, I failed to have my Z3801A drive my 58517A over port 1.
> Appling 5V on the SMC connector on the 58517A solved the 
> problem. The same Z3801A was feeding the active antenna with
> no problem just a few minutes before, so it is not an issue on
> the Z3801A.

I've got/had both varieties, and some time ago I mapped out the circuits.

To be clear (for non-smart spliiters):

If it has the SMC jack, external DC power must be supplied via the SMC jack.
All of the output ports will sink some current to make receivers happy, but
they will not power the amplifier.

If it doesn't have the SMC jack, power must be supplied via PORT 1.  All of
the other ports will sink current to make receivers happy, but they will not
power the amplifier.

It is easy to convert the external DC version to work with DC on PORT 1.  It
just takes a (1206, IIRC) shunt -- the pads are right there near PORT1.  It
is a good idea at the same time to pull the current limiting resistor in
series with SMC jack so as to disable that input.

-ch