ground loop problems? --HDBOX PRO

[Xenphor]

Hello,

I basically just registered to this forum to ask a question regarding the hdbox pro. I've been having the same problems that some others have been having regarding wavy and scrolling lines. The effect seems to be diminished at higher resolutions such as 720p but I can still notice a ripple going through the screen. I guess I have what is called a ground loop?

I've tried switching vga cables and component cables but that didn't help. I tried plugging the power cable of both the hdbox pro and the monitor into the same wall socket and that didn't help either. When they are plugged into separate sockets the problem also persists. I'd rather not have to remove the ground from my monitor's cable because of safety reasons. I'm guessing that adding a ground to the hdbox's cable wouldn't help anything? I've never had a problem like this before in all my years of hooking up stuff so I'm not sure what's going on.



edit: oops sorry, meant to post this in the hdbox pro thread.

[Trevor spencer]

ive had the same problem when connecting my 360 and PS3 upto my Plasma when i was using 720P component at 1080I it was gone

very annoying problem , id like to know how to fix this too

[Xenphor]

Too bad. At 480i the effect is quite bad, almost to the point where large parts of the screen appear to be rippling in addition to having a scrolling line.

[Ex-Cyber]

What signal sources are plugged into this setup? If you have a cable TV or satellite cable hooked into the system anywhere, that could be the source of your ground loop since those cables are often grounded at different points than your electrical system.

[Xenphor]

Well it's an lcd computer monitor so it only accepts a vga signal. Normally I have a vga switch setup to it to connect my computer and xbox 360. I have tried it without the switch, using a direct connection to the monitor with nothing else connected. I still get the same type of distortions. I should also note that I have tried a similar direct connection with another CRT monitor I have and I get the same effects. None of these are hooked up to the TV, cable, or anything else.

[Ex-Cyber]

Are you sure that the outlets you're using are actually grounded?

[Xenphor]

Well no. I guess I assumed because all the outlets have grounds that they would be grounded. And I assumed that if they weren't I would've had a problem with something else by now. Is there anyway I can test to make sure?

[Ex-Cyber]

Well no. I guess I assumed because all the outlets have grounds that they would be grounded. And I assumed that if they weren't I would've had a problem with something else by now. Is there anyway I can test to make sure?

There are testers that you can plug into the outlet, though they can't detect every possible wiring problem (I think you can also do equivalent tests with a voltmeter, but you need to know what you're looking for and I don't remember the details of measuring AC outlets). The thing with the ground pin is that pretty much nothing actually depends on it. It's primarily a safety feature.

Anyway, it could very well be that the ground connection is correct. These kinds of problems are not always easy to track down.

[Xenphor]

Well if we could just assume for a moment that my outlets are actually grounded, is there anything else I could try to do to fix the problem?

[drewmantrivia]

I had the same problems that you have brought up when I was running my HDBox Pro on my 36" RCA TV through the VGA port. I got wavy lines and some colorshift depending on what system I was using. So I did these things to try and remove the problems.

-Make sure the power is a grounded outlet.
-Use a grounded powerstrip and plug only the monitor/TV, HDBox Pro, and what ever system you are using into the same strip.
-Use a known good well shielded VGA cable that has ferrite cores on the end. If you can get one that has all 15 pins in the heads and make sure they are all connected. (It can help with some weird sync issues for some monitors at higher resolutions) A shorter cable should be a bit better than a longer one. Here is one I have used in the past.http://www.monoprice.com/products/produ ... cification
-I got rid of the crap power supply from the vendor and used a higher powered 5v one. Later I dumped that one and built a filtered and grounded power supply that seemed to clear up the rest of my problems. RGB32 had a thread over at Gamesx that caught my eye and I built a supply around his advice and what he had done himself.

After doing those things I never seemed to have any problems after that.

If you do all these things and you still have problems then I would start trouble shooting on stuff like. Video cords wrapped around speakers or powerstrips/power supplys. If your monitor is grounded you might need to use a ground cheater to lift it from ground since the powersupply for the HDBox is not grounded. Do you have your PC hooked up through the HDBox Pro as a switch? That caused me some problems with ghosting when it wanted to send on or the other signal through. I just only left it plugged in when I did games and went back to my PC on a seperate VGA cable.

I'd say try those things one at a time or all toghether and see if anything changes for you. If anyone is intrested I did document my build of my power supply and I could post it. It helped for my setup so maybe it would for you guys. It wasn't hard just more dinking around to scrounge for parts to get it how I wanted for my self.

AJ

[RGB32E]

I got rid of the crap power supply from the vendor and used a higher powered 5v one. Later I dumped that one and built a filtered and grounded power supply that seemed to clear up the rest of my problems. RGB32e had a thread over at Gamesx that caught my eye and I built a supply around his advice and what he had done himself.

After doing those things I never seemed to have any problems after that.
...
I'd say try those things one at a time or all toghether and see if anything changes for you. If anyone is intrested I did document my build of my power supply and I could post it. It helped for my setup so maybe it would for you guys. It wasn't hard just more dinking around to scrounge for parts to get it how I wanted for my self.

AJ

Glad to hear that my advice helped!

[drewmantrivia]

Yeah you rock man! When i get time i will dig out my photos and post the build here. I found a fused EMI filter w/ a switchable power plug that is used on medical machines. Was under 5 bucks so it totally worth it to add just not to dink around with a power switch.

Waiting to hear on your work on that Wii HDMI adapter. Sounds like it would be a winner if you can get the insides mapped and that info on the chip going. Keep it up man!

[Xenphor]

Hmm I tried hooking all my stuff up to the same grounded power strip and still got the same problems. It actually so happens that I have been using a couple of those VGA cables from monoprice so obviously they aren't the problem. I think the power supply is probably the main issue here as it does seem pretty cheap. The only problem is that I don't think I have the technical know how to actually build one myself. I have no background whatsoever in doing stuff like that. Is it possible I could buy one from somewhere maybe? Or is there any other way I could improve upon the existing power supply? You mentioned that you bought one before building one yourself. Was that any good or did the problems still persist until you made one? Thanks.

[Ex-Cyber]

Building power supplies isn't terribly hard. The hard part is designing them.

[drewmantrivia]

The 2nd power supply i used was a old Zip drive power supply that i had to rewire the tip to make it work.

Fun Tip of the Day!!! -Always use the right polarity for power!

But anyways it was a way more heavy wall wart that had more power than the original one. It gave smooth power but still wasn't grounded. In my case I still feel that is what made the difference was RGB32e suggestion of a switching power supply and EMI filter setup for the incoming power to the switching power supply. Here is the thread that got me started with building my power box. It started with some the knock-off HDBox Pro converters that can be found on ebay.
http://nfggames.com/forum2/index.php?to ... 4#msg26294

Give it a read see if it makes any sense. I will look on my other machine for photos and my parts list i came up with to build mine. Wasn't to hard but I had time trying to find the best enclosure for it so my wife wouldn't just toss it out or have my son poke fingers into a hot power lead. Got to love kids they always find the dangerous stuff like a magnet.

AJ

[Xenphor]

Hmm I'm still not sure about building a power supply. How safe/unsafe would using a ground cheater thing be? Would I just need one for the monitor? Do I also need one for consoles that have grounds? Does it matter how I combine them on the powerstrip?

[drewmantrivia]

Xenphor,
Using ground cheaters is not a great way to go but it is a way to work around problems till you can fix them. You would only need to use a ground lift/cheater if the device you plug in has a ground pin on the power plug like your monitor. It will do nothing for you if don't have that pin like on the HDBox power brick. Most old game system walwarts I have seen don't have a ground pin. The only ones i can think of that would have them now would be the PS3 and the 360xbox. No real need to use them with the HDBox in my mind then.

[Xenphor]

Why wouldn't it be a permanent solution? Because of the safety issues? If it works I think it may be the only solution for me because I'm quite certain I won't be able to build a power supply myself. I'd mainly be using it with a ps2 which doesn't have a ground anyway so it looks like it would be just the monitor that has it.

[drewmantrivia]

I'm not saying that you couldn't do it as a permanent solution but as a safe long term solution for your monitor's safety I wouldn't do it. Its not like they put the grounding pin there just to be a PITA, rather it is to help protect the monitor. I personally don't do it for my gear but each to their own.

I work with pro audio and video gear for my job and having grounded and properly powered equipment makes all the difference when it comes to interferance in your audio or video input/output. I have gone out of my way to build a power box for my converters because I found out I could it myself without a huge price tag. Is it the way to go for everyone? No. But it worked for me and I took my time to do it right so I had few mistakes as possible.

I did find some of my photos of the box i made. I'll post the one i found and some of the parts on Ebay that i bought and used.
http://cgi.ebay.com/New-Corcom-EMI-Filt ... 2eadb0a428http://cgi.ebay.com/DC-5V-3A-15W-Switch ... 563d4f9a39

And for the jack i used either the M or the N from radio shack. I can't remember what one it was but i was trying to use the same sized one when i made my own power cables. Just check the size with the old power supply if you need too. http://www.radioshack.com/product/index ... Id=2102489

[drewmantrivia]

http://farm5.static.flickr.com/4016/470 ... aa739a.jpg
http://farm5.static.flickr.com/4033/470 ... d64e_b.jpg

[HDgaming42]

RGB32 had a thread over at Gamesx that caught my eye and I built a supply around his advice and what he had done himself.

This sounds interesting. I can't find it over there--care to shoot me a link?

[drewmantrivia]

RGB32 had a thread over at Gamesx that caught my eye and I built a supply around his advice and what he had done himself.

This sounds interesting. I can't find it over there--care to shoot me a link?

Sorry I miss spoke. He had made a note in a thread about the Vbox HD-360 and talked about power supplies. It is the same link as above.
http://nfggames.com/forum2/index.php?to ... 4#msg26294

[RGB32E]

Looks nice and clean! Great job Drew! Did you obtain the case from an old switcher and paint black (perhaps I missed this earlier)? Also, looks like you have somthing Extron in the lower right hand corner of the picture:

[Specineff]

I noticed that some of you are using either a Plasma or LCD display. When I tried this with my Vizio, and my brother's Sharp, I got the scrolling line of doom. Same with my ACER LCD monitor.

BUT

when I tried it on a humble Dell CRT computer monitor, worse I had was a bit of static/interference, only noticeable against solid black or white screens, and at a very close range. It seems that CRTs eat interference for breakfast, given they use a different technology than LCDs. Or at least can solve that ground loop issue. I'll perform further tests and report my findings.

[drewmantrivia]

I have tried the HDBox with my power supply on graphic workstation CRT monitors, 4x3 lcd's, 16:9/10 HD capable LCD's, and my old RCA 36" pro-res TV that had VGA inputs. I have hooked up all with fully pinned VGA cables (all 15 pins) and with VGA cables that have not been fully pinned out. I have tried using Extron RGBHV BNC to VGA cables with BNC to VGA adapter to hook it up on the monitors above. I had really good luck with a 50' run of Extron RGBHV Vga cables with little to no ghosting.

CRT's for the most point will be better for the HDBox because they don't suffer the re-draw rates that some LCD monitors have. Especially older LCD monitors have horrible draw rates. The next thing to think about is how high do you want to set the output resolution of the HDBox. If you want to upscale a 480i signal up to 1920x1200 yeah you might have some interference that will come from cranking it up that high. That doesn't do anything about the power grounding it is just a part of the output of the HDbox. Your best bet is to find the the standard resolution of your monitor what ever type it is and set your HDbox to that. On a CRT you should not really need to go much higher than 640x480 or 800x600 if you are doing 480i stuff. There is no need to push it more as if I recall the HDBox processes every signal no matter what it is. I have found running a PS3 at 1080p will look ok at 800x600 on a CRT.

LCD's are a bit different depending on type. LCD's for computer monitors can be great if they have standard set resolution that it will lock to. For the most part the standard resolution will be set at 60hz. I have seem some LCD's that will do 75, 72, 60, and 59 and change. Best bet is to try to start with 60hz and see if you can get a clean lock with that.

LCD TV's that have a VGA port on the back can have some issues. Some manufactures have set the max resolution of the VGA input to 1024x768 stretched, some widescreen but not full 1080p spec. Most will be set to 60hz so shouldn't be a problem there unless you are tied to a single resolution or aspect ratio. My LG Tv had a sub menu that would let me do a auto sync to my VGA port that i had to find to make it work the first time I hooked up to it. After that it has gone will for getting setup.

I have access to a lot of different monitors (plasma,LCD, Prosumer, Crt, Projectors) at the school I work at so let me know if there is a set up you would like me to try Specineff. I have both a HDBox Pro and a Vbox HD-360 with the original power supplies if you would want me to test anything out.

Peace!

[drewmantrivia]

Looks nice and clean! Great job Drew! Did you obtain the case from an old switcher and paint black (perhaps I missed this earlier)? Also, looks like you have somthing Extron in the lower right hand corner of the picture:

Thanks for the praise man! You got me thinking on the passive cooling so I could leave out a fan that may cause noise on the power line. So i got a old switch box (good eye) and tack welded a plate over the holes and dremeled out my slots on the back. I drilled out vent holes on the sides and bottom for air flow. I added a 5v USB connector for my Ipod and external HD drives for movies. The power supply had an adjustment for the output so I set it as close as i could under full load. I can run both my Vbox HD-360 and HDBox pro at the same time without any power drops.

Yeah that is a Extron tweaker in the corner. We buy a lot of their hardware for our school so I have dozens of those things around. I shove them all over so i have some where ever i am so i can crack stuff open when ever. When I was at Infocomm in 08' the Extron booth had barrels full of their tweakers' for people to grab and take. The funny thing is you already have a ton of them if you deal with them anyways so the joke was no one wanted to take anymore than what they had already have.

[Xenphor]

Hm, a crt monitor didn't help with my signal quality at all really. I still noticed the scrolling line and the same type of wavy distortions. I guess there's not much else I can do at this point as I don't really want to use a ground lift permanently.

[ZOM]

I just plugged an USB cable in one of the 2 additional plugs on the HDBP's PCB and power it through my PC.

[drewmantrivia]

I just plugged an USB cable in one of the 2 additional plugs on the HDBP's PCB and power it through my PC.

What version of the HDBP do you have? I know there are bare board versions and different knock off boxes but I haven't seen one with a usb header. Did you add one to it or did you get the xecutor one from Team Xecutor?

[ZOM]

I have the bog standard, metal-enclosed, HD box Pro:



If you look at the PCB you'll see a white 4-pin connector and pads for a second connector on the PCB...
On one of the connectors the middle two pins have GND & +5v, on the other you'll find GND & +5v on the outer pins.
Coincidentally, I had a spare USB-cable from a mouse which has a similar connector on one end (but obviously it's 5 pins), so I just soldered two pins on the pad with the missing connector to plug in the USB cable:



And here's a shot of my awful dremel-work on the backside of the box :