Screen just gives bad static and white lines

[ManicMan]

Hi

I'm working on a portable Megadrive (using a Mk2 board) and the screen i'm currently using s a cheap 'ps2' 'Playon' screen which is a Casio CMV54NT04P with a control board to give speakers, brightness etc. It uses a Standard Composite to Jack connection.

when connected up to my Megadrive via a Megadrive AV cable (cut), croc clips attaching the wires to the cut cable for the Screen, I can get sound without problem. When I connect the ground for the video and then connect the video, the screen powers up (back light turns on, doesn't when no video (and ground) is connected and transmitting) BUT I just a couple of static white lines on the screen and red waves left and right of the screen. I have tested the Megadrive on a TV and it works fine, when I test the screen on a DVD player, it also appears to work fine (I get an image for a start). So i'm not sure what's going wrong here. Sound is no problem, by the way.

I wondered about a resistor problem so I tried a 75ohm resisitor on the video cable but that made no difference at all.

While it's not quite as 'bright/light' as this image seams to show, here is a photo of the problem

Any help would be grateful. While it is designed for a 12v car adaptor, I'm using a 12v 250mA plug adaptor which seams to power it fine. While I would have took the White lines for being screen damage, they don't appear when I have used the screen on something else, so I'm not sure.

 

[ManicMan]

Okay, minor update

I decided to try what I have got as the main battery source for the final build, and that is a rechargeable Lit-ion battery which outputs 10.8-12.6VDC (6800mAh) and this time, the screen still turned on, but instead of any image (which doesn't relate to anything that should be on screen) the screen had NO displayed image of any kind but created interference on the audio.

which sounds like a grounding problem.. but probably isn't.

EDIT: more then a new post..
Tested again on DVD player, via plug adaptor, I could get an image, via battery a bit of flicker (no noticeable image) and static interference on the audio channel. Changing battery again just in case it's enough charge to power up and all, but not enough to get it to work right now. Still nothing on trying to get the Megadrive to correctly output to it.

EDIT 21/2 - more information
The Casio CMV54NT04P is the same as the Sharp LM6Q401. I do have the screens pinouts but don't see too much use for them right now, but maybe for someone.

EDIT 22/2/ - more again
after a little while on battery, the static interference on the audio stops and the screen image is just black with a few white bars.. the difference from that and the original photo is no red waves.. think this has something to do with the graphics failing.. maybe incompatible graphics res.. but I can't see how it could be a problem..

 

[ManicMan]

might as well make this another post..

been searching around and this forum again (not even the second time) and some hints that a black screen with white horizontal, and the buzzing sound at first, might be related to not having it shield right.. well.. right now, the first stage is testing the parts together.. so they probably aren't shield.. the grounding wire for the Composite (the ground seams to go from the single pin, splits into three before connecting back in, probably together, can't say right now) is attached via electrical tape to the grounding wire for the console.. I'm using a standard AV cable for the console end, which normally goes to three jacks, but I've cut off the Video one to test the wire more directly for now. the two audios are left on. the composite wire itself I'm just touching to the other end wire (which is connected to small phone jack) and go into the screen).

I have tried to touch the screen's cable wire to the console directly and nothing difference happens, so, along with testing both wires out, I have ruled out a bad wire as a option.

checking the screen (not the board's) connections directly might be tricky.. the Screen has 10 pins, which counting left to right, on the first row and then the second are:
1 - unknown/ na
2 - Blue
3 - Red
4 - +12v
5 - Ground
6 - unknown / Na
7 - Composite Sync
8 - Green
9 - +12V
10- Ground

Now a problem are the colours for the cables that connect to the board from them. there are 6. a batch is together, which is Yellow, White, Red & black, and two loose ones which are Yellow and white. I would have thought the 4 together are probably RGB and composite, and the loose two are ground and +12v...

I could probably try the screen directly, having to guess the colours but I don't personally think it's going to do any good.. nor can I really see it being a shielding problem right now.. this is just driving me nuts ¬_¬ and the only skilled electricians I know that could help are dead.. sigh..

 

[ManicMan]

Screen has probably had it.. second one I went through so i'll have to fine another type..

when I connect to the mains and to my DVd player, the image is pretty bad with some white lines.. se below (sorry for the blur but it's not much but mostly due to the focus on such an image a this)

with battery, it's mostly black with some coloured lines moving and flicking.. backlight appears on though..

but PSone screens are SOOO pricey this days, it's out of my range.. might be worth getting a third one of these screens... I think there was a pop when I plugged something in but not sure what yet..

EDIT:
While I might be able to deal with the Horizontal hold, I'm no closer to dealing with the other problems, so I have brought a new screen which, is slightly different from what I want (it's 16:9 instead of 4) it looks like it might be better. A car screen for twice the price. I'll see what happens.. worse case, I can use the screen for something else.

 

[ttsgeb]

Maybe the screen is super picky about what signal level it will accept. Try passing the signal through a dvd player or vcr, and see your screens handle it better.

Also, the screens could just hate PAL, and if that's the case, it could just be burning out because it's getting a signal it doesn't expect.
There might be a jumper on the screen to select between PAL and NTSC, though. Maybe have a look for that?

 

[ManicMan]

possible.. i'll have a chance to test it tonight but I'm wondering if a 75 ohm resistor doesn't affect the level, I wonder how much passing it via something else will help.. but i'll try it.

I can't find a jumper or anything that might switch the signal type.. the closest I can see is a orange plastic screw head attached to the line that goes to the colour adjust switch. there is some weird metal screw on the board labelled VX1 which could be anything, doesn't go all the way through the board though so probably some kind of adjustment.

it's a cheap thing made for PS2's so probably not much good and I have another screen on it's way anyway so.. i'll toy around and see what happens.

 

[ttsgeb]

Something like that? That's called a potentiometer, pot, variable resistor, or rheostat if you're really old. It's used for adjusting things. If you have a turn-wheel volume control, it's one of them. There are also two of them in every analog stick, as they are what make them work. They're pretty swell and super useful, as long as Link doesn't come anywhere near them.
I would advise against messing with it, but I also won't stop you. Experimentation is a great way to learn, especially if you already consider this fubar'd. What's the worst you could do?

 

[ManicMan]

yep, looks like them, but the other side of the metal cage I think ^_^

EDIT: I'll also try to take a photo or two of the screen internals.. worse case and I get this screen working, I can use the other screen for something else

 

[ManicMan]

not enough time to do too much checking yet but I've confirmed the screen IS PAL. When plugged into the DVD player, which gives bad image, I switched the DVD players output to NSTC and the image completely went being replaced by pretty much a white screen. I think they confirms it is PAL.

VHS player only has one scart and an RF in/out which is a pain cause I don't have a MD2 RF connector that I know where it is, and the scart would probably be needed to attached the screen, so I can't filter via that. DVD player isn't a recorder so no input there either. I'll have to check with TV itself a bit later

 

[ManicMan]

... unable to test going via something else right now.. annoying but oh well..

in case anyone is interested, here are the internals of the screen.

Control board. Headphone jack on either side, AV jack input below one of the headphones (on this image, far left bottom of the board). power button, power jack the three 'wheels' in the centre, which you can see two of them connected via the gray cables are Colour, Brightness and Volume. Speakers are under the board. The gray ribbons seam to be very badly dealt with and the connections will brake almost as soon as look at them.

Now the inside of the screen itself

Images aren't that great, but might be useful for .. something.. New screen should turn up between Monday and Wednesday.

 

[ManicMan]

new screen turned up today, pretty early which is nice.

bit confusing though.. it is a cheap one of course.. two types of video connector, VGA or Composite. but the red (audio right) has a different type of plug.. it looks Male instead of female). there is also a Blue wire that isn't connected to anything.. not quite sure about that one right now..

the power is also confusing.. a small jack one end, the other just the wires end.. so the power isn't attached to the screen at all..

screen seams to be.. JWS-JX0701570D102a15 which means nothing to me..

images to come

EDIT: Never mind.. i'm an idiot and wasn't thinking.. of course the RCA is like that.. and of course about the power too ^_^;

EDIT 2: and still no images
Appears to work fine.. Powers up from my Battery pack, Plug the RCA into the megadrive and I get picture. Though it says there is Sound (well, it says there is and there clearly is, a way to turn sound up and down) I can't get any sound. This seams to be because there is noplace for the sound to connect to. while there are speaker grills on the back, I see no speakers inside and the three RCA connectors are just two different composite ones (AV1/AV2) and the power. so it seams it doesn't come with speakers.. which isn't a problem as I got speakers that work from my other screen. I might need to figure out the attaching side of them though.. since it has a onscreen menu for buttons like Sound up and down, it seams stupid NOT to use it.. but I would need to work out the correct way to connect.. also still bothered about that blue wire.. wonder what it is..

EDIT 3: Image

again, sorry for it not being very good but oh well.. the board is pretty small on this one. the first set of wires, which have the connections labeld on the board, is the VGA, the next one is the AV.. Red and Black for Power, Yellow for Composite 1, White for Composite 2, Blue for I don't have a clue. it's just a long loose wire that isn't connected to anything.

I'm slightly worried about what looks to be the spaces for a chip with 16 pins, a space for a battery and the other bit which might be related to speakers, cause it might mean hooking up a set which would use the screens controls might be a bit harder then expected (if a chip is missing.. that would be a real pain).. but worse case, I just need to go with the wheel control from the other screen.
the big chip like a processor says MST703-LF, which marks this as a nice cheap little screen that people seam to find is okay. I also have the data sheet for it (207 pages).