Re: More FireLite debacles

Looks like you have wrung the thing dry and the only thing left is the
FireLite box. Have you tried plugging the box into a regulated and filtered
power supply instead of the wall wart? Hell. I see even that wouldn't answer
the question of why the thing doesn't work on battery. The only thing (other
than the audio being picked up on all the "antenna" wires) is perhaps you
need to try a dead bang electrical ground solid to each component and to the
same grounding point because as you say, the entire system floats with
respect to the AC supply. That "should" kill any signal caused/allowed by
the float. Chasing gremlins is a momma bear sometimes and sometimes it is
the most basic of things that was forgotten in the design of new hardware.
Like ensuring the equipment stays neutral in an environment filled with EM
signals. Note too that "earth" is not always "earth" through two different
"earthed" rods. For instance I know of one case where the main line was
split with one section going to a shop remote from the house and EVERYTHING
was the same except for that 4th wire. Each panel had its own grounding rod.
Equipment was wired as normal in the shop and there were all sorts of
glitches. Come to find out there was a potential between neutral and ground.
It was cured by running a separate ground wire from the shop rod to the
house panel and removing the house rod.

--

Don Thompson

Remmy sez,
Count de Monet.
Unless, of course, you are Baroque.


"Lloyd E. Sponenburgh" <lloyd.sponenburgh@xxxxxxxxxxxxxxx> wrote in message
news:4stFe.18474$iG6.2297@xxxxxxxxxxxxxxxxxxxxxxxxxx
>
> "Don T" <-painter-@xxxxxxxxxx> wrote in message
> news:CNsFe.4665$0C.4264@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> Lloyd,
>>
>> Have you looked for a "floating ground" fault? I say this based on your
>> comment that the CD is on a different branch circuit than the audio amps.
>>
> Yes. That would have been a potential source of 60Hz AM in the time code
> (but not likely, see below). More likely, it would superimpose 60Hz on
> the music; you'd hear it coming out the amps. The output to the time code
> equipment is not fed to or through the amps. The amps are on the same
> phase as the CD, just not the same breaker. But there is no electrical
> ground, only a signal ground between the CD player and the firing
> equipment. The FireLite is used on internal battery power during a show,
> and only connected to the AC charger between shows. There also exists no
> electrical ground (common to the local power ground) for the firing
> network, only a signaling ground and a "firing power" ground. The modules
> all derive their power from the firing controller. The entire system -
> network and all - "floats" with respect to the AC supply. But FWIW, I
> tried the system with the AC supply connected, too. There is an AC
> neutral leg "ground" on the charger, but no earth ground, and only 2-pin
> AC into the FireLite charging input. The wall wart is a simple
> transformer, not a supply/regulator.
>
> Besides, I saw no 60Hz noise on the time code line, only a random 2db
> amplitude jitter that appeared to coincide with the music audio. 60Hz is
> pretty easy to see and recognize, even at small levels. I didn't have the
> time or equipment channels to do subtractive analysis of the noise itself,
> to see if it matched the music waveforms. But it's a pretty good guess,
> since the noise doesn't appear until the amp stack is up to about 3500
> watts of output.
>
> BTW, that's one reason we used a low-impedance drive with equipment-end
> impedance matching. But again here, we've also run the system on a 600
> ohm line-level output with _exactly_ the same results. And we've changed
> CD players (even different brands), and branch circuits. The only thing I
> don't like about the branch we're on is it's also powering the fluorescent
> room lights (which are OFF during a show).
>
> One other possibility is that the entire firing network is acting like a
> big antenna, sucking up 60Hz, and back-feeding the CD output. But again,
> there's no visible AC superimposed on the signals to the F1 or the
> Aquilla, either between their signal ground and the signal, or between
> earth ground and their signal.
>
> And don't forget -- the Aquilla is physically on the same time code _wire_
> as the FireOne. It sees the code just fine, and is working on the same
> circuit as the CDs.
> There CAN be an electrical ground at the Aquilla box. The Aquilla can
> operate either on standby battery power or AC, and the performance of the
> system, et. al., does not change.
>
> We wrung out a potload of possibilities. The installation has YAG and gas
> lasers, too. We moved all the audio equipment physically distant from the
> argon/krypton and HeNe lasers, because they tend to broadcast in the .5 to
> 1 meter frequency range. But they're well-shielded, and doing that didn't
> change the situation. The YAG projectors are external to the building,
> and remote, so we didn't do anything with them.
>
> LLoyd
>
>
>
>


.

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