I wired up a homemade VGA cable this afternoon using the LM1881 IC. Better picture than using the ghetto and basic component to vga cord. Larger board also has a LM1881 sync stripper to provide a clean. From an Extron CrossPoint, VGA switch, or RGB interface without needing a.
DIY – LM1881 Sync StripperThis page will show you how to use an LM1881 chip to “strip” the sync information from composite video, for use in an RGBs video signal. If you’d like to buy a pre-made sync stripper, please.Please note that the LM1881 outputs TTL-level sync. If you’re going into a device that’s expecting 75 ohm video-level sync (such as the framemeister), then you’ll need to add the 470ohm resistor to the output line. There’s more info at the bottom of the page and for more information on sync, please see the.Parts Needed:You will need basic tools (more info can be found in ), plus the following items for this circuit:–, such as pliers, tweezers, etc.– Soldering iron / solder– Basic soldering skills.– LM1881M chip, the SOIC version (please see the links to the right for the chip) —– One– Two– One (if 75 ohm csync output is needed)Board Assembly:This is a fairly easy circuit to build, but there’s a few tricks to make it smaller and easier. Also, this guide assumes you’d like to use a mounting board (thanks to the guys on the neo-geo forum for the idea). You can use if you’d like to solder directly to a chip, but this is a “cleaner” way to make the circuit. I’ll walk you through it step-by-step:– This is the main LM1881M chip you’ll be using (surface-mount, SOIC version) and it’s relevant pins:– Start by adding solder to both the chip legs and the pads on the board, by heating the area with your soldering iron and then touching solder to the metal.
I got used to doing this on a desk, but using a stand and alligator clips will make it easier:– After applying solder to both, use pliers or tweezers to hold the chip while you mount it to the board. Once it’s lined up, you should be able to just touch your soldering iron to it and they will solder together:– Next, you’ll want to use a multimeter to check your solder points. When checking, make sure to touch the pin where it enters the chip, not near the bottom where you may accidentally be making contact with the circuit board’s pads.
Then, touch the other tester to the pad that matches it’s input. If a connection isn’t made, you could try adding more solder to the joint between the pad and pin:– Add a to the hole that corresponds with pin 2 (composite video in) on the LM1881M. I suggest using a multimeter to double check that the hole on the board matches the pin on the chip:– Then add a to the holes corresponding to the arrows below (once again, I suggest using a multimeter to double check the holes to pins between the chip and board). Also, make sure that the resistor isn’t touching any of the pins on the chip, or touching the other holes on the board. I have mine run above the board to ensure it’s not touching, as shown in the bottom-right picture:– Next, solder a to the resistor. I like to solder it as close to the resistor itself as possible, to make sure it’s not touching anything else, or touching to board’s pads.– Finally, solder power and ground, as well as composite video in / csync out:– After you’re done, it’s good to cover the circuit with heatshrink tubing, so you won’t risk shorting it out (or anything else around it).– That’s it!
Overall, it’s pretty easy to make and is a bit smaller then soldering it directly to the chip. I actually fit one of these inside a VGA head and for use with my N64! Also, it makes for a much cleaner look. That being said, if you prefer the chip-only solution, you can check out:75 Ohm csync outputPlease note that this guide shows you how to build the sync stripper circuit; It does NOT talk about use case scenarios. If you’re plugging this into a display or video processor (such as the Framemeister) then you’ll need to add one to attenuate the output to 75 ohm video standards.
Many RGB monitors accept a wide variety of sync signals, including the TTL sync that this circuit outputs. If you’d like to be safe, just add the extra resistor; It’s literally as easy as just soldering it to the output pin.That’s it! A pretty easy circuit that can really come in handy! If you’ve arrived at this page as part of the, please move along to:. If not, feel free to head to, or check out for everything else we have to offer.
Requires a EuroSCART cable which is wired for either 5 volts or 12 volts on pin number 8 of the SCART plug. This is needed to power up the LM1881 video sync separator circuit and without this required voltage you will not get a stable picture on your monitor. Please see diagram below which shows the location of pin 8. If there is a wire attached to this pin then you should be good to go.
If you are unsure whether your cable is wired correctly please contact us for assistance. All video game console RGB SCART cables from Retro Gaming Cables are compatible with the video sync separator version.