AVS Forum banner
Status
Not open for further replies.
1 - 20 of 20 Posts

·
Registered
Joined
·
39 Posts
Discussion Starter · #1 ·
I have had sp 7200 for about one month. Installation is ceiling mount and 100 inch diagonal Firehawk 16:9. Image is wonderful with HD materiel (cable HD box Pace 550 from Warner Cable). DVD is generally excellent depending on transfer. Connection is component video 30 foot run. Standard 480i materiel is generally of poor quality. Would image be better with composite cable. I do have VHS connected (used with tuner is cable ready s-vhs vcr) and image is about the same as with component connection? A second problem are vertically ascending horizontal lines that definitely worsen when room lights are on or dimmed and decrease when lights are off (but do not completely disappear). These lines are visible through component and s-vhs connection. I believe they are 60 cycle electric noise. Anybody else had this problem? What is the best fix? Would line conditioning help for electric and cable? Any thoughts would be appreciated. Thanks
 

·
Registered
Joined
·
67 Posts
Line noise can significantly degrade the performance of electronics.

I have a sophisticated component audio system and about 3

weeks ago I added a balanced power line conditioner

(Furman RI-1220). It noticeably decreased the noise floor, and

improved transparency and clarity. I suspect the same would

apply to video image quality, and I'm planning to use it on my

front projector when my HT room is completed. Balanced power

conditioners are expensive, however they essentially

eliminate the problem of line noise and ground loops.
 

·
Registered
Joined
·
5,756 Posts
Sounds like a ground loop problem as far as the lines in the picture go.


If you're complaining about the image quality on standard television broadcasts, that is just the nature of the beast - crappy. I can't imagine that using a lesser quality connector would improve things, but you could sure try it.


Good Luck!


JOHN
 

·
Registered
Joined
·
4,076 Posts
If you don't need power conditioning but you do have some ground loop, is there any in-line device (between plug and socket) one could use just to eliminate the ground loop but still have grounding?


Thanks.
 

·
Registered
Joined
·
320 Posts
I agree with John, SD material just does not measure up. If you are looking at the SD stuff coming out of the cable box and the Hd stuff looks fantastic the likelyhood of a cable or ground problem doesn't seem possible since you are using the same input device and cable. I have heard that a good power conditioner can make a difference in signal quality both audio and video but that would be a pretty steep price and there would still be the disparity between the SD and the other material.



Tom
 

·
Registered
Joined
·
2,364 Posts
I would first get rid of the dimmer and see if that eliminates the problem.


Next I would turn off circuits at the fuse box one at a time to narrow down where the horizontal line noise originates. Then check your 30 foot run of component coax cables and move them away from any power.
 

·
Registered
Joined
·
882 Posts
your lights are on dimmers, right?

The lines don't occur when the lights are all totally off, right?

That was my experience.

The Lutron microprocessor dimmers did it.

Plus I noticed that via DVI there was no problem but via component there was.

HTH.
 

·
Registered
Joined
·
39 Posts
Discussion Starter · #9 ·
The lines (hum bars) diminish with the lights off (Lutron Spacer dimmers) but do not completely disappear and remain visible with DVD as well as cable (both SD and HD materiel). I need to view DVD with the cable disconnected to see if this eliminates the hum bars. I will also check with my cable company (Warner) to see if they offer ground loop isolators) or can help me with ground loop issues. Thanks for the feedback. Greg
 

·
Registered
Joined
·
1,609 Posts
I had the same problem, cable tv was bringing in the problem and my parasound 2205 amp was magnifiying the problem it all went away when I plugged everything into the same outlet including my 7200,(it also happened on several other pjs too) so I use a monster 2600 it does the job and you can plug everything into it.



Good luck, Bob
 

·
Registered
Joined
·
39 Posts
Discussion Starter · #11 ·
I had a dedicated 20 amp circuit run just for the projector and it terminates in the ceiling 25 feet from the main equipment stack. I'm not sure how I can get the line to the equipment stack. I could run a heavy duty extension through the suspended ceiling or run romex 3 wire to a new outlet box near the equipment stack. I have outlet by the equipment stack I am using but, of course, they are on a different circuit and hence the ground potential difference and the hums bars. Suggestions welcome. Greg
 

·
Registered
Joined
·
1,609 Posts
I run an extension cord to my rack through my drop ceiling, its probably not the most recomended thing to do but it works:)


I would suggest that you at least try plugging everything into the same outlet including your pj, use a powerstrip to test it if you have a lot of gear and run the extension cord from the pj on the ground to test it first.


If it does fix the problem then you can think of fixes later:(



Bob
 

·
Registered
Joined
·
882 Posts
I still say it's the dimmers.

I had to go two levels (up to the 2nd floor) & turn those dang Lutron Spacer dimmers off or full on to totally get rid of mine. PJ is in basement.

It wasn't just the ones nearby doing it.

(I have the same exact Lutron Spacers.)

I temporarily ran an extension cord from another circuit near the main breaker without any improvement at all.

Also, I noticed that when I fed it via DVI from the TimeWarner 3510 box there were no lines, regardless of dimmer setting.

But via component the dimmers cause those [email protected] lines.

Good luck!
 

·
Registered
Joined
·
3,102 Posts
Also, check your firmware version.


However, it does sound like a groundloop. Are there any power cables or lines running with or perpindicular to the video cables?
 

·
Registered
Joined
·
371 Posts
I had the same issue after installing Lutron dimmers. Solution number one solved 95% of hum bar issue (still visible on blank screen if looked very closely). This solution was removing the ground wire from the plug. Not really recommended.


Solution 2 took care of the problem completely, which was plugging the projector into the same circuit as the Lutron dimmers (which is where all other equipment was plugged into to start with.


In other words, at least in my case, the issue was that the components and dimmer were on one circuit, the projector was alone on another.
 

·
Registered
Joined
·
371 Posts
Another possibly solution is something like the Richard Gray Pole Pig. It completly isolates the equipment from the ground. This is a very expensive solution, thoough. There may be other equipment that does the same thing for a lesser price.
 

·
Registered
Joined
·
39 Posts
Discussion Starter · #18 ·
Problem solved! Plugging all components including projector into surge protector with coax in & out completely solved the problem. The Lutron dimmers are causing no trouble. The hum bars are gone. Thanks to all who have posted and helped me fix this. Thanks, Greg
 
1 - 20 of 20 Posts
Status
Not open for further replies.
Top