matt can you please help. with the lm1881

[acem77]

can you please give me some help.
i have had no luck in getting the video to show up stable/sharp. i dont know if the am doing every thing right.
http://www.gamesx.com/misctech/lm1881.htm
i dont know if i ned to use the the odd/even out and or
the burst/back porch output. do i have to ground the reset?

[seen]

Some people should help people that are just learning electronics, and not leave them hanging.

That aside. You don't need the odd/even output, all you need is the composite sync out, pin 1, and set up the resistors and capacitors like the rest of the pic, there are two .1microfarad capacitors(anything more is just fine, like 10V 10microfarad or something, get radial ones), and a 680 kilo-ohm resistor, 4 is ground, 8 is +5V. The capacitor marked "||" on the right should have it's negative end "-" connected to the ground. The polarity(which end negative) on the resistor doesn't matter.

email me at floormaster01@hotmail.com if you have any more problems. I'm pretty sure you can figure this out.

[matt]

Some people should help people that are just learning electronics, and not leave them hanging.

I'm sorry, but I've got bills to pay and college courses to pass, and those come first.  I will try to be helpful when I can, but I just can't be checking different internet message boards every day babysitting people who've gotten in over their heads.  When I first said that that component converter worked for me, I did not say that it would be easy to use or that it would work right away.  This is supposed to be a technical forum, and there should be an understanding that you need to get your hands dirty in order to make things work.

Anyhow, Seen is right - you don't need any of the extra stuff - just the sync pins and the composite video input.  On the cable I made, I routed the comp sync output to the VGA connector's Hsync pin, and the Vsync output to the Vsync pin.  BTW, 0.1 uF capacitors generally aren't polarized, so you don't need to worry about which way you place them.

If you need a cable made, I can do it.  However, please be aware that I've only used the converter out with the one TV set, so I can't guarantee 100% that your TV would like it.

[seen]

The only reason I said what I said was because I didn't want him to get discouraged so quickly. Learning electronics can be very difficult on your own. It's good that I have my grandpa to help me, but I realize that others may not be as fortunate. I understand that it isn't your priority to help him, I have a several software projects I am working on as well, and am occupied 90% of the time. I still do my darndest to help out noobs.

Actually, I wanted to build two projects using the RGB->component setup. The world's smallest JAMMA rig and a MAME game console type of machine which among other things would let you switch between 3 arcade boards and the computer emulator(s). Let's hope I have time to do that.

[acem77]

thanks for trying to give me a hand.
being a noob to video mods i need any help i can get.
i can understand how some noobs can annoy and waste your guys time.
but i am a good learner. there is some hope with me.

here is the last thing i did for my self.
i think it is cool i used the service manual schematic to see where i could talk to the camera. and now with this trick you can get more mega pixel and fast shutter speeds with more range to the f-stop.
http://www.agoraquest.com/viewtopic.php?to...c=8624&forum=31

[benzaldehyde]

Hi,

    It would seem that you're not that unfamiliar with technology, acem. :lol: However, there is always the chance that the unit is defective. Does Audio Authority have something like a 90-day warranty? It may be too late to return it, but they may still be able to help you. If all else fails, it might be their fault!  

[acem77]

i was thinking about that. it may be a chance it is broken.
i need to bug a freind with a high def set.

[matt]

thanks for trying to give me a hand.
being a noob to video mods i need any help i can get.
i can understand how some noobs can annoy and waste your guys time.
but i am a good learner. there is some hope with me.

Don't feel too self-concious about beeing a noob - we've all been there before.  Most people will try to help out, but we may be slow about it sometimes.

Trying it out on different TVs is a very good idea - you may find that it works better on some TVs than others.  We tried my friend's 9a60 on a smaller Phillips TV a little while ago, and it didn't work at all, even though it runs fine on his 27" JVC.

I've also had good luck recently with the RCA VHDC300.  I think it gives a slightly better picture, and it usually sells for pretty cheap (mine was $50 from Ebay).  The picture seems to be a little too far to the left sometimes, though.

[Darklegion]

I haven't tried this yet and I'm pretty new to electronics my self but you might want to check page 5 of the lm1881 datasheet(get it at national.com if you haven't already),halfway down under composite sync output.Apparently if you wire up 620 ohms of resistance in series with the composite video input and a 510 pf capacitor to ground this will filter out any extra crap in the sync that is occasionaly there depending on the source.Also you might want to try more than 1 source(of video) as some may have better quality sync than others....even try a console that supports composite sync,wire it up and see if the picture is stabler.
Another idea I just thought of is that you tv doesn't like composite sync fullstop without the video,maybe you could get the lm1881 to output the burstbackporch output,and then combine that with sync and run it in as normal composite video but I don't how well that would work or if you'd need extra electronics to get it working well...worth a try though.

[matt]

Also you might want to try more than 1 source(of video) as some may have better quality sync than others....even try a console that supports composite sync,wire it up and see if the picture is stabler.

I haven't had any luck using the composite sync output from any console.

One thing you might want to try would be using a DC VGA box with a 15khz mod.  I haven't gotten around to trying this yet, but it might work - the DC will give separate sync, and it's probably at the same level as when it's running in VGA.