I just set up my Panasonic PT AE700U. So far, I love it. I am a total newbie to this stuff though; I've surfed this and other sites, and there seem to be a lot of knowledgable folks here. Recently I noticed an annoying distraction. I have horizontal lines of color that scroll up the screen. There are two thin greenish lines closely spaced (about 10% of screen height max) followed by two purplish lines (also closely spaced) about half a screen height below. They slowly march up the screen, then reappear at the bottom and do it again: green, purple, green, purple, etc. They are present when watching both cable TV and DVD.
I'm wondering if my setup has anything to do with it. I have a Yamaha RX-V750 receiver, which up-converts video inputs to a single component video output, which is good because my room layout doesn't allow a ton of cables to the PJ. So my DVD and cable box input to the Yamaha and I have a long run of component video cable, approx 42 feet (actually one 6' and three 12' Radio Shack "Gold" three-prong A/V cables with male-to-male adapters), to the projector on a shelf on the back wall. (Not an ideal setup, I know, but my room does not allow too much flexibility.)
So I'm wondering if this anomaly I'm seeing is a known defect, if it can be "tweaked" out, or if it's a function of my MacGyver-esque setup (not intended as a self-compliment), or worse, a faulty PJ. Has anyone seen this? Any ideas out there?
Oops. I hope I didn't mess something up. I tried to start a new discussion, and now the BBS isn't showing any of the old threads under the "projectors" topic. If I have screwed things up for anyone, I am truly sorry to all. Like I said, I'm a newbie.
Anonymous
Posted on
even if its a temporary configuration, you got to setup a clean top quality HD signal to properly test that AE700u when you first buy it, otherwise you will never know if you got a defective unit needing immediate exhange
this means a straight connection to that HDMI input on the AE700u - from for example a DVI/HDMI output on a hi def cable box or hi def satellite box, or even a new generation over the air box from Samsung etc with these connections
2nd best would be a component output to component input run, to test for the HD signal that way
if you use a clean hi def setup and nothing is wrong with the AE700u - you will get ultra-clear hi def pictures
forget about any "upscaling" - you will not isolate where the problem is otherwise and forget about sound initially. Its very important that the unit produces an ultra sharp and intense color picture. For example an 8 foot diag picture from an 8 ft viewing distance will look basically like in-theater quality sitting lets say 20 rows back in a commercial theater
(as a side note) watch the shutdown procedure - its 2 step - and press down the main botton 3 to 4 seconds and then wait as the fan stays on for several minutes and eventually automatically shuts down the fan - before you swtich it off using the switch in the back of the unit or simply instead just leave it in standby mode
turning on is quicker of course, it takes only a few seconds, no heat issue
I am unware of any common defect on this unit and given the volume sold over the past few months and high demand, such defects would soon become apparent.
Thanks for the input. I'm still waiting on an HDMI signal to test that feed. I've got the startup/shutdown procedure figured out too. In the meantime, the original problem still exists, but I've done more troubleshooting in an attempt to isolate the source. I checked the OSD menu, as I've heard people on this site talk about tweaking the flicker adjust. I've got all my colors set to 1D, which apears to be flicker-free. Still have this "horizontal banding." I examined some of the projector's test screens - none of them have any visual artifacts of any kind, so I think the PJ is good-to-go. I tried bypassing the receiver altogether by hooking the DVD component output directly to the PJ - the "HB" is still there, so it's not the reciver either. So I figure it has something to do with the long run of component video cable. I tried "building" a component cable out of three 50' RG6 shielded coax cables, thinking that the problem could have been the couplers between the 12' lengths letting noise in. The problem actually got worse, so I went back to the old setup (one 6' and three 12' lengths of component cable coupled together end-to-end). So I think I've isolated the problem to signal losses incurred by the ridiculous length of the cable run (again, it's 42 feet). I guess my next troubleshooting step would be to carry my DVD over next to the PJ and hook it up directly to the PJ using a short run of cable, or maybe try a different input to the PJ (HDMI when I get an HD cable box, or S-video). Either that's it, or I'm missing something else entirely. Anybody have any other ideas? By the way, the banding looks different now - it appears more like a single thin greenish horizontal line followed about a 1/3 screen height distance below by a single, thin purplish line. The space below the green line has a slight green tint, and the space below the purple line has a slight pink/purple tint. The lines still alternate green/purple/green/purple and still scroll bottom to top. It's getting more annoying...
Anonymous
Posted on
MAXWELL what your seeing is real. I'm a AE700U owner with over a 1000 hours of use. I purchased this unit back in Nov 2004. The unit has been awesome until recently. I have the purple lines also that come and go now. It acts like fluid between the layers in the LCD. It will tint the whole screen. I reboot the machine and it goes away. And sometimes it comes back again. Seems to be getting worse the more hours that I put on it. I have a good clean HD 1080I setup with dish network. but it does this in all modes when it happens. I have found no way to stop in in the options or picture settings. I am going to contact the service people about this issue.
I have the exact same issue with my BenQ PE7700. After extensive troubleshooting I found that the problem will go away if you only use a 6ft. component cable. I believe this to be a manufacturer defect (cold solder joints adding resistance) as I have had no problems running 50ft. of component on other projectors I have owned. I am in the process of purchasing a signal booster. If that doesn't work- its going back to BenQ to be swapped.
Horizontal scrolling lines is usually (but not always) a ground loop. Unfortunately tracking that down can be a hassle, but as pointed out earlier in the thread start with one source (preferably DVD) and nothing else even connected and the source plugged into the same electrical circuit as the projector. If the problem goes away there's nothing wrong with your projector!
have gone though the ground loop troubleshooting process and this did not fix the problem. Ground loops usually represent themselves as audible hum or black and white scrolling bars- not colored bars. I effectivly combined two high quality cables to get about 18ft. without any problems. After 18ft. it is noticible. The problem is I need to run about 30ft. from my component switcher to the projector. I think the signal booster should take care of things as it appears to be a velocity of propogation problem with the 50ft. Stellar labs cable I am using. I will re-post once I have it installed.
I just installed a Panasonic PT-AX200U projector and last night, watched a couple of DVD movies. Towards the end of the first movie, we began noticing two scrolling lines - one red and one green, spaced about 1/2 screen height apart. The longer the projector was on, the brighter the lines seemed to get. Using the projector's screen test pattern, there are no scrolling lines, so I doubt the projector is the problem. The lines occur using both of our Hi-def upconvert DVD players, as well as our Hi-def cable box. All 3 of these components are connected to an Onkyo TX-SR605 7.1 channel receiver via component cables. I also have a VCR connected to the receiver via an RCA composite cable. A 25-ft component cable runs from the receiver to the projector. The projector is on a different electrical circuit than the rest of the components. The projector is plugged into a small 1,100 joule surge protector and the rest of the components (including the sub woofer) are plugged into a Monster AV home theater 1,700 joule surge protector (which also has a coaxial cable pass through being used). Has anyone else had this problem or have any ideas of solutions? Thank you!
I had this exact same problem on my BenQ projector a while back. The fix ended up being a cable ground loop isolator. The ground of my incoming TW coax was at a different potential than the rest of my equipment. I disconnected the coax from my cable box and the problem disappeared. Once I installed the isolator, no problems whatsoever. Hope this helps.
Ryan - Thanks so much for your reply and helpful information. I'm searching online for an isolator and it looks like Jensen makes one for digital cable and cable modem applications, and it runs around $59.00. I found a cheaper one for under $10, but it looks like it's for analog applications only. Tomorrow, I'll call the dealer where I bought the projector and ask if they carry the isolator. I also may try using a cable ground to see if that solves the problem. I have a spare satellite one (we tried satellite very briefly) and may throw it on to see what, if anything it does to the picture.