EDIT...

[zedrein]

OK, so my LM1881 sync separator actually arrived today, whoo hoo! But there is absolutely no indication about where the composite video in and horizontal and vertical sync out are located--there are 4 pins on each side of the chip, so I need to know which side is the indicator where I need the appropriate pins. Also, when looking at the chip I notice that I am going to have to solder directly onto the legs? I thought that there would be holes where I would put the wires.

One more thing, I noticed on this sites' page for the chip that there is a diagram for a 0.1uf cap for composite video input--do I have to get another cap, or is it already built into the chip? Anything else I need to know before using this chip?

Thanks for the help!

For reference, here's the 1084's RGB connector: http://www.allpinouts.org/index.php/Commodore_1084_&_1084S_(Analog)_Video

(On the 1084 from the sync separator will I need to bring out both the horizontal AND vertical syncs, or just the horizontal?)

[undamned]

I have a 1080 series monitor and it does indeed require composite sync., not composite video.  This is based on running my PS2 w/ and w/o an 1881 and it is not possible to get a stable picture w/o an 1881.  As far as modfiying your SNES cable at the console end or waiting on the 1881, it's all a matter of time/labor/parts.  If your cable has a composite sync pin on the console connector (and you can open it) you just need to be willing to put out the time/labor.  If the pin is not avail. just wait for your 1881 to come in.

And yes, it's ok to shorten the legs of capacitors, just make sure you solder the polarity correctly and don't yank the pins out of the bodies, heh.
-ud

[Fudoh]

It's been nearly a decade, but my 1084 monitors definitely all worked without sync strippers, so composite sync should be perfectly fine. The 1084 always have been marketed as kind of multi-use monitors not just for Amiga setups.

[viletim]

OK, so my LM1881 sync separator actually arrived today, whoo hoo! But there is absolutely no indication about where the composite video in and horizontal and vertical sync out are located--there are 4 pins on each side of the chip, so I need to know which side is the indicator where I need the appropriate pins. Also, when looking at the chip I notice that I am going to have to solder directly onto the legs? I thought that there would be holes where I would put the wires.

There's a notch on the top of the chip, the pin to the left this is pin 1. You count them anti-clockwise from there. Check the datasheet (first page) for a pinout.

One more thing, I noticed on this sites' page for the chip that there is a diagram for a 0.1uf cap for composite video input--do I have to get another cap, or is it already built into the chip? Anything else I need to know before using this chip?

The capacitor in series with the video input is essential. The cap & resistor connected to pin 6 is only required if you need the vertical sync output.

LM1881 outputs composite sync and vertical sync. This model of Commodore 1084 (Philips) will accept composite sync on either the horizontal or vertical pin. No need for vertical sync at all.

[Drakon]

uhm....according to that pinout you don't need a lm1881

it already has horizontal and vertical sync signals coming out of the commodore.  My rgb to s-video encoder board supports both combined H+V sync signal or seperate horizontal and vertical syncs.  The LM1881 is for STRIPPING a sync signal out of a COMPOSITE VIDEO signal.

[zedrein]

uhm....according to that pinout you don't need a lm1881

it already has horizontal and vertical sync signals coming out of the commodore.  My rgb to s-video encoder board supports both combined H+V sync signal or seperate horizontal and vertical syncs.  The LM1881 is for STRIPPING a sync signal out of a COMPOSITE VIDEO signal.

Yes, but my SNES SCART cable does not bring out composite sync, it brings out composite video, and according to most when you try to feed a composite video signal to the horizontal sync input on a Commodore 1084 monitor, it won't read it. That's why I was debating whether I should simply rewire my SCART cable at the SNES' end, or just wait on a LM1881--but now that my sync separator has arrived, I am kind of plagued by more things I didn't have knowledge about, please refer to my other thread on this forum, "LM1881 Sync Separator"

http://nfggames.com/forum2/index.php?topic=3480.0

[NFG]

Yes, but my SNES SCART cable does not bring out composite sync, it brings out composite video, and according to most when you try to feed a composite video signal to the horizontal sync input on a Commodore 1084 monitor, it won't read it. That's why I was debating whether I should simply rewire my SCART cable at the SNES' end, or just wait on a LM1881--but now that my sync separator has arrived, I am kind of plagued by more things I didn't have knowledge about, please refer to my other thread on this forum, "LM1881 Sync Separator"

I guess that's why viletim suggested you not create a new post for variations on the same topic, eh? 

Also, I recommend creating links for other members to follow instead of making them search for 'other threads on this forum'.  It's just ultra-helpful when you do.

[Tiido Priimägi]

IIRC, NTSC SNES have composite sync out, instead of the 12V line in PAL SNES'...

[zedrein]

IIRC, NTSC SNES have composite sync out, instead of the 12V line in PAL SNES'...

Yes you are correct sir, however the SNES SCART cable only brings out composite video, not composite sync, so to my knowledge I need a LM11881 sync separator chip to strip the sync signal from the video signal.

[Tiido Priimägi]

Can't you just re-arrange pins in the connector ? I can open the SNES side connector and with some small tools I can get a pin out and position it elsewhere...

[MKL]

Can't you just re-arrange pins in the connector ? I can open the SNES side connector and with some small tools I can get a pin out and position it elsewhere...

It depends on the cable. The non-official ones I've seen don't have crimp pins but solder pins that can't be moved and there's no pin for +12V:

[zedrein]

Can't you just re-arrange pins in the connector ? I can open the SNES side connector and with some small tools I can get a pin out and position it elsewhere...

It depends on the cable. The non-official ones I've seen don't have crimp pins but solder pins that can't be moved and there's no pin for +12V:

The last time I tryed to open the connector at the console end, I ruined it, so I'm going to play it safe and use my sync separator.

http://nfggames.com/forum2/index.php?topic=3480.0

[Drakon]

okay I bought some snes scart cable from sweden.  And I opened the connector on the snes multi AV end.  Luckily the cord I got has all the pins.  So I just resoldered the composite video wire into the composite sync pin.  It wasn't very hard to do.  Then all I had to do was add a capacitor and now I'm rockin' and rollin'.  Honestly it's much easier hooking up the composite sync pin than building a lm1881 circuit.  here's the cable I bought

http://cgi.ebay.com/SUPER-NINTENDO-SNES-FULL-RGB-SCART-LEAD-CABLE-BRAND-NEW_W0QQitemZ370127357563QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item370127357563&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

[zedrein]

okay I bought some snes scart cable from sweden.  And I opened the connector on the snes multi AV end.  Luckily the cord I got has all the pins.  So I just resoldered the composite video wire into the composite sync pin.  It wasn't very hard to do.  Then all I had to do was add a capacitor and now I'm rockin' and rollin'.  Honestly it's much easier hooking up the composite sync pin than building a lm1881 circuit.  here's the cable I bought

http://cgi.ebay.com/SUPER-NINTENDO-SNES-FULL-RGB-SCART-LEAD-CABLE-BRAND-NEW_W0QQitemZ370127357563QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item370127357563&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

I guess I'm going to have to buy that exact SCART lead, because I've had a whole night of bad luck.

Firstly I tried the cable with the LM1881 circuit, and I couldn't get a sync, the picture was EXTREMELY unstable, completely unplayable. Next I tried to open up the cable at the console end, and there is absolutely no way I could work through all that plaster-like shielding. I guess I was a little bit encouraged that I was able to at least get some sort of picture--It was pretty strange though, when there was little going on the screen like just text, the picture was fine, but when it came to gameplay, the picture was violently unstable...I wired up everything right, but still no luck.

[viletim]

zedrein,

Place a 75 ohm resistor between the composite video line and ground. The value isn't critical, anything from 500 to 50 ohms should work but 75 is preferable. It will very likely solve your problem.

[zedrein]

zedrein,

Place a 75 ohm resistor between the composite video line and ground. The value isn't critical, anything from 500 to 50 ohms should work but 75 is preferable. It will very likely solve your problem.

Since I know that you love my awesomely crude schematics, will you confirm if this is what the chip will look like with the resistor?

[viletim]

Directly in parallel with the video signal, before it passes through the LM1881 coupling cap.

This is definately a requirement for the PAL SNES because there's a diode in the signal path. No signal comes out until some current flows through the diode. For the NTSC I'm not so sure...

[Drakon]

I guess I'm going to have to buy that exact SCART lead, because I've had a whole night of bad luck.

Firstly I tried the cable with the LM1881 circuit, and I couldn't get a sync, the picture was EXTREMELY unstable, completely unplayable. Next I tried to open up the cable at the console end, and there is absolutely no way I could work through all that plaster-like shielding. I guess I was a little bit encouraged that I was able to at least get some sort of picture--It was pretty strange though, when there was little going on the screen like just text, the picture was fine, but when it came to gameplay, the picture was violently unstable...I wired up everything right, but still no luck.

uhm...you do realize for the cable I bought I worked through a crapload of plaster shielding.   I just had some patience and took my time and eventually CAREFULLY got it off.  What you're talking about with the weird sync happened to me too.  That's what happened when I hooked up my ntsc snes to my encoder using composite video for sync.  Sometimes it would work....sometimes it wouldn't.  Getting that plaster stuff off around the console end of the plug is a bit of a pain but all it takes is some patience.  And it's much easier than building a lm1881 circuit