Non-VGA screen to VGA

xxMIKExx · 03-31-2007, 11:33 AM

I have a Pyramid 7" TFT LCD screen that has a composite video input and i want to run VGA because composite is fuzzy. I have read about the PSone screen mod and attempted it with my screen. When i took my screen apart i was able to determine the where the RBG signal is made from composite then fed to the monitor controller board.

Just like the PSone screen there are two seperate boards-one board that has some kind of chroma decoder and another board that connects to the lcd panel and backlight. On the first board there are three contacts on the bord that stood out to me and i touched each contact to a ground and one would cause the screen to flash red, one would cause the screen to flash blue, and one would cause the screen to flash green.

i soldered small wires to each of these contacts and attached them to the corresponding color on my VGA graphics card. There are two graphics cards on my computer and i would change the scan frequency on the card with the pyramid lcd with powerstrip and use the other screen to see what i was doing. I got some video on the LCD but it was flickering really fast and you cant make out anything on the screen.

Can anybody with experiance please help me.

henkbliek · 03-31-2007, 11:40 AM

You might need to connect the sync (HS, VS) signals too.
Probably not easy to find the proper 'insert points' though.

Motorcity · 03-31-2007, 07:08 PM

, but if you were able to determine RGB on the board, I think you should be able tyo locate sync. But, it might not be seperate H & V, but combined. I do not know if you can combine the 2 from your vga out.
Please post some pics of your findings.

xxMIKExx · 04-01-2007, 12:43 AM

I'll try to take some pics and post them when i gat a chance.

xxMIKExx · 04-02-2007, 08:27 PM

Here are some images of the Pyramid LCD. Sorry about the quality and lighting, my digital camera is broken so i had to take the pictures on my MOTOKRZR. In the pictures you can see the small board that i have soldered red, blue, and green wires on to that are the red, blue, and green input like a VGA monitor (sorta, i think). Anyway i was able to get a very fuzzy and blinky picture on the screen as I said above but it looks like crap and i need help. The IC in the closeup is a "AN5372S" the data sheet can be found here: http://pdf1.alldatasheet.com/datashe...C/AN5372S.html

Motorcity · 04-03-2007, 12:34 AM

ok,
after looking at the datasheet, and my notes for another pc to monitor project, I think you can do this:

If your monitor has a single sync input (composite sync) you can connect the H-Sync and V-Sync wires together. The PC VGA card always sends negative H and V sync in all video modes, so this method works fine.

So, if you were to combine H & V sync and connect to pin 15 of the IC, hopefully it works.

But, I assume no responsibility for what may or may not happen. If you are willing to take the gamble, then by all means please let us know the results.

Good luck

xxMIKExx · 04-06-2007, 04:01 PM

Connecting H-sync and V-sync to pin 15 helped alot, Thank you! Also, if I connect H and V sync to the video input instead of pin 15 it has the same effect. Anyway, I've been messing with powerstrip a lot and this is the best i could come up with so far:

The first picture (if I uploaded it right) is a picture of the screen displaying my desktop. The only problems are that there are two of them =-/, it is too small, and the display slowly scrols along the screen, but the one on the right has a good picture and all the colors are perfect. The second picture is a closeup of the good side on the monitor. and the third is a picture of my setup i use to do the **** with, i have an lcd monitor and a tv and the display spans accross the two so i can change the frequencies and stuff on the other graphics card and see what im doing.

sxott · 04-06-2007, 04:32 PM

This is really very interesting stuff. If you could get this to work it would be a great boon to everyone here.

Motorcity · 04-07-2007, 01:05 AM

keep us updated. It looks like a little moe tweaking will be all that is needed to get that display running stable.

xxMIKExx · 04-07-2007, 10:24 PM

I've done more tweaking and was able to get one single picture and i got it centered but it blinks really fast and the colors are off slightly. Getting closer though

.

Motorcity · 04-07-2007, 11:45 PM

sounds like the refresh rate may be off. I am not sure, can you adjust this in powerstrip?

xxMIKExx · 04-07-2007, 11:53 PM

Yes you can adjust the refresh rate with powerstrip. The only problem is getting the correct refresh rate.

trueppp · 04-09-2007, 06:25 PM

what pins did you connect RGB to???????AN5372S

xxMIKExx · 04-10-2007, 10:18 PM

I didnt connect it directly to AN5372S, there are some resistors and such in between the contacts I soldered the wires to and the IC. Im quite sure I have it connected to pins 17, 18, and 19. If you look at the datasheet it sais those pins are for red (17), blue (18), green (19).