Scart to DVI, I want to know if my monitor accepts 15khz there...

Started by timofonic, May 03, 2009, 01:34:29 AM

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timofonic

Hello.

My monitor is a HP LP475W]. I'm interested in using it for connecting some of my retro devices.

Some people say me that certain TFT monitors are able to accept 15khz signals over DVI or VGA inputs, so I would like to know if mine is able too and use it then.

Anyone could provide me a schematic for converting a scart/RGB to DVI (to the analog pins, no conversion)? It's probably simple, but I understand little electronics and only able to make simple PCBs based on certain schematic.


Regards.

EDIT: Someone said me that I need little more than a LM1881.

I also found this:

http://www.lupinesystems.com/articles/syncsep.htm

QuoteLM1881 is not a good solution. Better to use Elantec sync separator. You can find the complete schematic in the Elantec datasheet
from http://www.edaboard.com/ftopic28803.html

QuoteEL4581C sync separator - The EL4581 extracts timing information from standard negative going video sync found in NTSC, PAL, and SECAM broadcast systems. It can also be used in non standard formats and with computer graphics systems at higher scan rates, by adjusting a single external resistor. The EL4581 provides a reliable method of determining correct sync slide level by setting it to the mid-point between sync tip and blanking level at the back porch. This IC can be considered as an improved version of popular LM1881. From http://links.epanorama.net/links/videochips.html#syncsep

kendrick

Tim, I've deleted your duplicate topic. Watch out for the Post button, it likes to be pressed unexpected. :)

timofonic

Quote from: kendrick on May 03, 2009, 04:44:23 AM
Tim, I've deleted your duplicate topic. Watch out for the Post button, it likes to be pressed unexpected. :)

Sorry. But there was aditional info there. My intention was not duplicate, but a more general post about those chips as LM1881 is quite popular in certain mods.

EL4581, EL4583/ISL59885 vs LM1881. What one is better?

It seems those chips are superior in features and also need less electrical power. What do you think? How to replace schematics using LM1881 to this?

ken_cinder

I've done it with 2 LCD HDTVs, nothing more than a homemade breakout cable..........no extra stuff like an LM1881. One TV required composite sync on the H+V pins and the other only on the H pin.

I say just try it straight up and see, and if it works THEN put more effort into a cleaner/nicer looking solution. Adding capacitors on the color lines if necessary etc

Get a multimeter, and just match your wires to pins on the DVI connector for the analog pins, plug it in and see what happens.

http://en.wikipedia.org/wiki/Digital_Visual_Interface

timofonic

Quote from: IJTF_Cinder on May 03, 2009, 01:41:57 PM
I've done it with 2 LCD HDTVs, nothing more than a homemade breakout cable..........no extra stuff like an LM1881. One TV required composite sync on the H+V pins and the other only on the H pin.

I say just try it straight up and see, and if it works THEN put more effort into a cleaner/nicer looking solution. Adding capacitors on the color lines if necessary etc

Get a multimeter, and just match your wires to pins on the DVI connector for the analog pins, plug it in and see what happens.

http://en.wikipedia.org/wiki/Digital_Visual_Interface

I'm worried about putting the signals directly, and most consoles output composite sync only as some people said it on the forums. Do you mean your TVs accepted composite sync over the hv sync pins without separating the signals? It's over DVI too?

What about this schematic? It seems interesting, converting VGA to DVI is just a matter of easy wiring.

http://pinouts.ru/VideoCables/scart2vga_scheme_pinout.shtml

I also think the schematic could be simplified and improved by using the ISL59885 IC instead the ol' LM1881, making it easier to manufacture too. This chip purports all kind of weird sync and able to output both horizontal and vertical syncs with just one IC.

ken_cinder

Yes, they accept composite on the H/V pins on the VGA connector on my TVs. Neither have DVI ports though, really no point to that when HDMI is DVI with audio.

timofonic

Quote from: IJTF_Cinder on May 04, 2009, 04:53:41 AM
Yes, they accept composite on the H/V pins on the VGA connector on my TVs. Neither have DVI ports though, really no point to that when HDMI is DVI with audio.
I'll get a component cable for wii. If it can output works a 240p from Virtual Console game (megaman 2?), then going to test 15khz over DVI analog pins.