Sync Stripper (LM1881) sync question...

goombakid

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Anyone who uses the LM1881 to get the sync signal from composite video; Is there any harm if pure composite sync goes where composite video goes in?
 

Yodd

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Anyone who uses the LM1881 to get the sync signal from composite video; Is there any harm if pure composite sync goes where composite video goes in?


No.

Many times you can take dirty/out of spec composite sync and run it through a LM1881 and clean it up and bring to a usable state.
 

goombakid

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That's good to know. Thanks, broken.

And just to get my curiosities out of the way, for a PCE RGB mod, would there be any difference between using straight composite sync and sync stripped from composite video?
 

Skips

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That's good to know. Thanks, broken.

And just to get my curiosities out of the way, for a PCE RGB mod, would there be any difference between using straight composite sync and sync stripped from composite video?

The only time I have seen straight composite sync have a problem with an LM1881N is when using some of the older RGB cards on the BMV-201FU. That monitor detested composite sync going through any sort of sync stripper. When I had it I ended up just wiring all my systems for composite sync instead of using the LM1881N. Most PVM's and even the XRGB should not have a problem with it though. Its just something to be aware of if you ever went to one of those monitors or were wiring it up for someone else with one.
 

goombakid

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The only time I have seen straight composite sync have a problem with an LM1881N is when using some of the older RGB cards on the BMV-201FU. That monitor detested composite sync going through any sort of sync stripper. When I had it I ended up just wiring all my systems for composite sync instead of using the LM1881N. Most PVM's and even the XRGB should not have a problem with it though. Its just something to be aware of if you ever went to one of those monitors or were wiring it up for someone else with one.

I'm going the route of a CVS287 with my Wega and a GBS 8220 for my VGA monitors for the time being. I don't think I'll go PVM, so I'm probably going XRGB-mini next.
 

Skips

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I'm going the route of a CVS287 with my Wega and a GBS 8220 for my VGA monitors for the time being. I don't think I'll go PVM, so I'm probably going XRGB-mini next.

You should be perfectly fine then. The CVS287 likes the LM1881n.
 

Yodd

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That's good to know. Thanks, broken.

And just to get my curiosities out of the way, for a PCE RGB mod, would there be any difference between using straight composite sync and sync stripped from composite video?


You need to amplify composite sync on all PCE systems. But once you do that I haven't heard of any differences.

Personally, I just use composite video as sync for PCE installs.


And the XRGB mini loves the lm1881. I use one inline with mine for everything regardless of composite video or composite sync being used as sync. This prevents you from having to fiddle with the sync level adjustment on the mini for each different source.
 

goombakid

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You need to amplify composite sync on all PCE systems. But once you do that I haven't heard of any differences.

Ahh. I just checked the amp I got from you a while ago. I thought it also amped sync.

If I take composite video, does it need to be amplified as well?

When I get the CVS287, I plan to mod it so I can use locally sourced parts (really, just a DB9 since I have a grip of them) instead of using a SCART connector for input. I'll probably throw the sync stripper in there as well.
 

Yodd

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Ahh. I just checked the amp I got from you a while ago. I thought it also amped sync.

If I take composite video, does it need to be amplified as well?

Nope. The composite video is fine as is. And all PCE's have really, really great composite video output quality as well.
 

Yodd

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So if I was to go the PVM route, I don't even have to strip sync out?


Typically no.

Though some older 80's era PVM like clean sync and many other RGB monitors like the NEC XM29 and the common Commodore 1084's require a clean sync.


But the vast majority of PVM's will accept either as sync.
 
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