The two sync's?

[Keith Courage]

It's up to you if you want to add a switch or not. In all honesty it may be easier to just add RCA jacks to the rear of the system for regular composite and the two audio channels.

You may have to look around the board to figure out where the composite was cut at. Some people do it right by the AV jack and others do it near the hu6260 chip.

[thesteve]

personally what i found using composite as sync in a SCART cable was i needed to add a 470uf cap across +5 and ground (at the scart plug)  to eliminate the jailbars caused by the current through the cable ground caused by the sync separator

[Vimtoman]

Tried the cap and made no difference.

[MNKyDeth]

I will be trying this again on my SuperGrafx, just waiting for caps and a couple other items before doing it. I will let you all know how it goes.

[MNKyDeth]

Ok, so I was messing around again today with this.

I modded my Super CD-Rom 2 system for RGB output. Instead of pulling Composite Sync from pin one on the Din socket I cut off the leg so it wouldn't go through the PCB mounting hole.
I then ran a wire from the remaining Din socket leg to pin 22 on the expansion bus.

Now, in hindsight, I have no idea if pin 22 is Composite Sync or C-Sync. If pin 22 on the expansion bus is composite sync is it possible to get pure sync from someplace on the expansion bus port?

I was using this diagram of the expansion bus.
http://www.gamesx.com/misctec/pcebp.php


Edit:
After some more poking around I decided to continuity test from pin 44 on the 6280A on my SuperGrafx to the same pin on the expansion port and I had sound. So it is CSync (pure sync) on pin 22-C and not composite sync. It seems to work just fine where it wouldn't on my TurboDuo.

I plan on getting some SS's of this system with CSync to compare it to one with composite sync. I also have a Component mod chip here from Turbokon and if I get some free time I will slap that into a system so I can get a 3way compare on my framemeister.

[mickcris]

Csync and composite sync are the same. Think you might be referring to composite video where you are saying composite sync above?  The naming can be confusing.

[Vimtoman]

Diagram pin
Csync          "Pure sync"            is what you want .
Vid              "Comp video"         is what you cut off the din.