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Forum Index : Microcontroller and PC projects : CMM2: Screen being black
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LeoNicolas Guru  Joined: 07/10/2020 Location: CanadaPosts: 504 |
Hello I'm having a wired problem running some graphic apps, like the game Gauntlet, or when I'm trying to run my 3D API in 800x600 screen resolution. The screen seems to lose sync. I know that the application is running because the sound is playing even when the screen is black. Do you know what could be causing this problem? Video: https://youtu.be/wq8B-ajEhq4 PS.: I'm using a cellphone charger with 5V/3A output to power the CMM2. The CMM2 is connected direct to the monitor using a VGA cable. Edited 2020-10-13 06:48 by LeoNicolas |
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vegipete Guru Joined: 29/01/2013 Location: CanadaPosts: 1132 |
Do you have a different monitor you can try? Is the VGA cable tight? Any other dodgy solder connections in the sync portion of the CMM2 circuit board? I get occasional colour changes with mine, I think one of the green resistors is sketchy, although I haven't figured out exactly what is ever so slightly amiss. Visit Vegipete's *Mite Library for cool programs. |
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| LeoNicolas Guru Joined: 07/10/2020 Location: CanadaPosts: 504 |
Unfortunately I don't have a second monitor to test it. The monitor and the VGA cable are brand new. |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6283 |
Have you tried it with my test card program? https://www.c-com.com.au/mmhelp/testcard.htm Don't use mode 13 if you aren't running the latest betas That will see if it's your monitor or something in the programs. Jim VK7JH MMedit |
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| LeoNicolas Guru Joined: 07/10/2020 Location: CanadaPosts: 504 |
Hey Jim, thank you for your help I've run the test and this are the results: 1.8: OK 1.12: 100% Black screen 1.16: Black screen blinking 2.8: OK 2.12: Black screen blinking 2.16: OK 3.8: OK 3.12: OK 3.16: OK 4.8: OK 4.12: Black screen blinking 4.16: OK 5.8: OK 5.12: OK 5.16: OK 6.8: OK 6.12: OK 6.16: OK 7.8: OK 7.12: Black screen blinking 7.16: OK 8.8: OK 8.12: Black screen blinking 8:16: Black screen blinking 9.8: 100% Black screen 9:12: 100% Black screen 9.16: 100% Black screen 10.8: OK 10:12: 100% Black screen 10:16: 100% Black screen PS: Some modes / color depth are showing weird noise on the screen. The modes that are showing black screen (normally 12 or 16) have a lot of noise. Noise recording: https://youtu.be/q68SXMIKp84 Edited 2020-10-13 09:53 by LeoNicolas |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6283 |
Is your CMM2 a single board one or with the Waveshare module? If Waveshare, doing the oscillator mod should help the noise you are seeing. It might also fix the main problem but I haven't seen one that bad. I am surprised you are having trouble with so many modes. Have you tried a different USB cable? It does look like a power supply issue and your 3A charger should be adequate but cables are often the cause of problems. Many monitors have a facility for seeing the incoming video mode. On my monitor it is under the Information menu item. Jim VK7JH MMedit |
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| LeoNicolas Guru Joined: 07/10/2020 Location: CanadaPosts: 504 |
It's the Waveshare module. Do you have the link for the oscillator mod? |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6283 |
https://www.thebackshed.com/forum/ViewTopic.php?TID=12506&PID=153775#153775#152068 Jim VK7JH MMedit |
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| Seamus Newbie  Joined: 18/08/2020 Location: United StatesPosts: 13 |
Good day. For what it's worth, the modes that your table lists as blinking and black screens corresponds neatly to the same modes in which I am experiencing the worst video tearing with my own unit. Mine is a kit, built with a Waveshare module as well. I actually have some tearing on modes that you list as "OK", but they're minor as compared to the others. I'm currently waiting on the arrival of the oscillator that I ordered, but will be giving my board a thorough re-scrubbing along with the timing mod, just to make sure there isn't any leftover flux residue compounding the issue. Please do keep us updated on progress. [Insert clever signature here] |
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| LeoNicolas Guru Joined: 07/10/2020 Location: CanadaPosts: 504 |
Hey I've ordered the capacitor and crystal. When they arrive I'll make the mod and check if will solve the problem :D I'll let you know when I complete the tests with the mod. Thank you for all you help |
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| LeoNicolas Guru Joined: 07/10/2020 Location: CanadaPosts: 504 |
Thank you for all your help. Problem 100% fixed, all modes working perfectly.   |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6283 |
That's good news. Now the fun begins... Jim VK7JH MMedit |
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