David Kaye
2014-10-05 07:51:56 UTC
Let's run down the scenario: New DVR and I've replaced 3 cameras that had
rolling hum bars and video breakup. The new cameras had the same problem,
and adding to that was the fact the new cameras all had multi-colored video
lines as if they were some kind of alignment lines or perhaps distance
measuring lines. Here's a URL to a JPG photo of these mysterious lines:
http://s532650451.onlinehome.us/test/Camera Alignment Bars.jpg
Mysterious, no? The otherwise flawless tech support folks for Swann had
never seen them before!
Okay, rolling 60Hz bars and occasional picture tearing, along with the
mystery bars.
My first idea was a ground loop. Okay, that creates buzzing, etc. My
multimeter showed *some* ground differential between the power transformers
(aka wall warts) at the remote outlets and the outlet where the DVR is.
Some differential, less than a volt, and probably in the millivolts. BUT
KSFO is about 15 blocks away and they're running 5kw and they could well be
inducing enough stray RF to cause the multimeter to budge a bit. These
things happen. Put in an isolation transformer. No change.
What else? Ran a number of lonnnnggg extension cords from a camera wall
outlet to the DVR and plugged into the DVR circuit. No change.
Let's see. I hooked an old camera to the DVR via 60 feet of cable supplied
by Swann. The old flaky camera that I'd taken down sprang to life with
flawless video. Huh? If it works at the DVR over 60 feet of co-ax then why
not at 100 feet over the existing co-ax. Maybe there's enough of an
impedance mismatch to cause standing waves, etc. The could account for hum
induction and picture break-up.
The handyman was puzzling over this. "Uh, have you replaced one of the new
camera power supplies with a new one from the kit?" No, because there are
THREE of these cameras with problems. Gotta be something else.
I went home. I slept on it. I went in to the cafe this evening and cut out
the hard-wired transformer from the easiest available faulty camera.
Connected a new power supply.
VOILA! The handyman was right. The camera is flawless AND the color lines
have disappeared AND the camera is working in night mode, too. The motion
detector and recording are working properly. Everything is FINE!
So, what's the story? Looking at one power transformer and figuring that
the ones I can't get to are all the same (they look the same from a
distance) I look and notice that the it's rated for 300ma and given the
cable run, the originals were probably underrated and the capacitors had
dried out from overheating, which would certainly account for the 60Hz and
for the picture break-up.
So, my conclusion is that the 3 cameras with the problems ALL have faulty
power transformers. Now comes the job of climbing to the ceiling and trying
to replace them the easiest way, hopefully without climbing into the ceiling
crawl space.
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rolling hum bars and video breakup. The new cameras had the same problem,
and adding to that was the fact the new cameras all had multi-colored video
lines as if they were some kind of alignment lines or perhaps distance
measuring lines. Here's a URL to a JPG photo of these mysterious lines:
http://s532650451.onlinehome.us/test/Camera Alignment Bars.jpg
Mysterious, no? The otherwise flawless tech support folks for Swann had
never seen them before!
Okay, rolling 60Hz bars and occasional picture tearing, along with the
mystery bars.
My first idea was a ground loop. Okay, that creates buzzing, etc. My
multimeter showed *some* ground differential between the power transformers
(aka wall warts) at the remote outlets and the outlet where the DVR is.
Some differential, less than a volt, and probably in the millivolts. BUT
KSFO is about 15 blocks away and they're running 5kw and they could well be
inducing enough stray RF to cause the multimeter to budge a bit. These
things happen. Put in an isolation transformer. No change.
What else? Ran a number of lonnnnggg extension cords from a camera wall
outlet to the DVR and plugged into the DVR circuit. No change.
Let's see. I hooked an old camera to the DVR via 60 feet of cable supplied
by Swann. The old flaky camera that I'd taken down sprang to life with
flawless video. Huh? If it works at the DVR over 60 feet of co-ax then why
not at 100 feet over the existing co-ax. Maybe there's enough of an
impedance mismatch to cause standing waves, etc. The could account for hum
induction and picture break-up.
The handyman was puzzling over this. "Uh, have you replaced one of the new
camera power supplies with a new one from the kit?" No, because there are
THREE of these cameras with problems. Gotta be something else.
I went home. I slept on it. I went in to the cafe this evening and cut out
the hard-wired transformer from the easiest available faulty camera.
Connected a new power supply.
VOILA! The handyman was right. The camera is flawless AND the color lines
have disappeared AND the camera is working in night mode, too. The motion
detector and recording are working properly. Everything is FINE!
So, what's the story? Looking at one power transformer and figuring that
the ones I can't get to are all the same (they look the same from a
distance) I look and notice that the it's rated for 300ma and given the
cable run, the originals were probably underrated and the capacitors had
dried out from overheating, which would certainly account for the 60Hz and
for the picture break-up.
So, my conclusion is that the 3 cameras with the problems ALL have faulty
power transformers. Now comes the job of climbing to the ceiling and trying
to replace them the easiest way, hopefully without climbing into the ceiling
crawl space.
---
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