VideoGamePerfection.com | crippo2 | Activity

crippo2 replied to the topic Unstable HSync in the forum OSSC - Discussion and support

Sun, 12 Jan 2025 14:28:12 +0000

Marqs

Thanks for this information, I will look into points you have raised.

Not sure my technology will allow me to look at the issues involved, but I will do some research on that.

Presumably I can, go to the pixel clock to act as a trigger point, presumong both H & V Sync pulses are locked to that.

Alternatively I can inhibit the V Sync…Read more

crippo2 started the topic Unstable HSync in the forum OSSC - Discussion and support

Tue, 07 Jan 2025 19:10:59 +0000

I Last contacted the forum several years ago about a system, using OSSC (now upgraded to V1.8 with f/w 1.11a)

OSSC input is Analogue RGBHV to AV3. Sync pulses are negative going from 5v.

With the input disconnected the OSSC test screen displays OK on the target..

VSync is stable over time @ 49.99Hz, but HSync is unstable once the initial 2…Read more

crippo2 replied to the topic OSSC loses sync when receiving 13.75 Khz H Sync in the forum OSSC - Discussion and support

Tue, 03 Jan 2023 19:55:15 +0000

Thanks for your response
I can only surmise that the pixel clock rates changes are software driven in order to overcome a hardware limitation (cost/parts availability/design). The change, evened out over time (and possibly using an internal freewheel PLL within the display) might be the creative solution – who knows why, only that it happens and…Read more

crippo2 replied to the topic OSSC loses sync when receiving 13.75 Khz H Sync in the forum OSSC - Discussion and support

Tue, 03 Jan 2023 15:07:47 +0000

Apologies about the length of this post
Regrettably I misread the information I think I now better understand the problem I have.
In the 1st 2 seconds after switchon the OSSC syncs with 13.57Khz and an initial frame rate of 49.69 Hz increasing to 49.72 Hz within the 1st 2 seconds before sync is lost.
The frame rate appears to stay steady at…Read more

crippo2 replied to the topic OSSC loses sync when receiving 13.75 Khz H Sync in the forum OSSC - Discussion and support

Tue, 27 Dec 2022 12:46:23 +0000

An update from the earlier post.
If appears that the display is responsive to an LVDS pixel clock signal rathar than the H & V Sync signals also sent to it. The 6.678Mhz pixel clock counts cycles and synchronises the H & V Sync signals to them rather than just relying on the pulses created by the Sync generator. this magic hsappens in ICs for…Read more

crippo2 replied to the topic OSSC loses sync when receiving 13.75 Khz H Sync in the forum OSSC - Discussion and support

Tue, 15 Nov 2022 10:41:28 +0000

Many thanks for your response.
However I now think I was a bit hasty in tasking the OSSC input Sync selection process as an issue.
Having put both H & V Sync streams onto a Tek Scope, I see that after initially (say 2 secs) pure sync pulses, both of an acceptable size and shape, during which the OSSC syncs fine, both H & V pulses become…Read more

crippo2 started the topic OSSC loses sync when receiving 13.75 Khz H Sync in the forum OSSC - Discussion and support

Mon, 14 Nov 2022 19:52:44 +0000

Be Kind please this my first post and still trying to understand the best way to sort this out!
I have 2 early naughties St Nav Units. Both run Analogue RGB with separate HV Sync. They are respectively NTG1 and NTG2.

The NTG1 System is to have its display upgraded, from ancient Analogue to more modern Digital Display.

My setup is simple.…Read more