[FredK]

You’ve had it work with the OSSC?

[FredK]

For the sake of my own curiosity I built a composite mod and hooked it to my inty. I then fed that to the AV2 Sync on green and it was a no go also. I pulled out my Trs-80 color computer with a composite mod and the OSSC synced right up to that. Comparing the 2 signals (inty and Trs 80) It looks like the inty is missing the pulses for interlaced video. If anyone with the skills wants to work on something with me (while I have this stuff hooked up and it’s on the bench) maybe we could design a new AY-3-8915.

[FredK]

Thanks. I checked the schematics out. I’m a little disappointed that the TVP7002 IC is so finicky. I tried to see if it would sync off from the composite signal from the intellivision before it goes into the RF modulator and it doesn’t like that signal either. The sync signals from the intellivsion seem to be missing a few Horizontal pulses before and after the Vertical blanking and during the vertical blanking. For every other device I have ever seen this is not an issue, but apparently it is for the TVP7002. I don’t have a composite mod on my Intellivision so there is a small chance the signal voltage was off. If someone has a composite mod can you hook it to the sync on green and see if it brings the OSSC to life? I suspect it won’t, but be nice to rule it out.

So unless I am missing something I think it is because of these missing sync pulses, if so The only way to make horizontal and vertical signals the TVP7002 would like is to start with the clock signal 3.57mhz and try to divide it down into the correct timing. We’d need to sync that with the RGB output somehow so the clock dividers would have to look at another signal from the Inty to reference the timing with.

Fred

[FredK]

Okay so after hooking up the scope and checking the Composite signal that goes into the RF modulator I can see that it looks exactly like the timing signals that comes out of my RGB converter (IE they don’t have the H sync in the vertical) So I’m a bit stumped as that should be a signal that any composite monitor would sync up to no problem. I think I’m missing something here or the OSSC is using some sort of horrifically bad IC for the front end… Anyone have any suggestions? Is there a schematic for the OSSC? Maybe I can look at a datasheet and see what the problem with the OSSC is having.

[FredK]

GUYS!!! Sorry for the tremendous amount of time it took me to get to this, but alas I have an intellivsion on the bench with one of my RGB kits installed and hooked to an OSSC. It indeed does not sync to it… So let’s see if we can figure out why.. I think the first thing to try is see if we can inject the horizontal pulses into the Vertical signal.. It’s been awhile since I’ve messed with this so I’ll have to get myself back up to speed on what signals I even have available.

[FredK]

Good day Guys,

My name is Fred and I am indeed the designer of the Intellivision RGB kit. Someone emailed me and linked me to this. I designed the RGB kit several years ago and used the framemeister and the cheap Chinese HDMI scalers to test it. First I have no idea what the OSSC is, who makes it or what it is exactly used for. Keep in mind I’m not active in the console scene, so if this strikes you odd I apologize. I design and build much more for stand up arcade games so I’m more schooled on what is going on in that circle. If you’re just trying to inject the H signal into the V signal off the top of my head I think and and gate would work. I could certainly change the firmware on the RGB kit to make a signal like you show above, but I have no OSSC device to test it and I am unsure how it would effect the RGB working with the Framemiester and Chinese HDMI scaler.

[Author]

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