Postby michaelfish » Wed Feb 08, 2012 7:15 pm
Your idea of using a VCR may work, similar to adding a video enhancer to remove and restore the video synchronization portion of the signal. Anything you can think of to help with diagnosis is on the right track however, the root of the problem will still be in the mix, so if you want to find out what is causing the blinking, I would recommend further research. Let's also not discount the fact that the MX-1 may be faulty too.
I personally think that the scan converter's signal is not up to the MX-1's requirement for proper synchronization (a VERY significant signal needed in order for the MX-1 to do its job correctly). A video signal is a combination of many different kinds of signals (B/W picture, Color information, Synchronization information, Color timing signal...just to name a few) and they are all put together (thus "composite" video signal) that totals only 1 volt peak-to-peak. The portion of the signal that is most important to mixing video signals is the lowest 0.0 volts to 0.75 volts IRE (in a good signal). Among the many things that can cause problems with that portion of the signal are; long lengths {1) VGA cable (long) connects to back of computer}, a Y cable spitting the signal {(2) Red Y-VGA connector)}, radio frequency interference (RFI) {many VGA cables are not shielded}, etc.
In either case, the Grandtec manufacture states it works great with any TV, Plasma, LCD TV, Projector, but they did not mention video mixers. Video mixers must synchronize two or more video signals oscillating at 3,579,545 cycles per second from a voltage about 1 tenth of a volt, which is QUITE A TAST. There are no consumer TV's, Plasmas, etc. that mix two video sources, thus the video synchronization standard of the Grandtec does not have to be as perfect as what the MX-1 may require.
Since there is a lot going on, professionals use devices such as time base correctors (TBC) and yes, expensive scan converters, costing hundreds to thousands of dollars, in order to produce what the MX-1 does, only they do it better. The MX-1 is about the lowest quality there is on the TBC-assisted-video-mixer-scale and was never designed to synchronize computer VGA signals. It uses S-Video or composite video. That is why a scan converter is needed - to take a video graphics array (VGA) and convert it into a composite video signal. Computer's graphics are not based the National Television System Committee (NTSC) signal, and thus an intricate conversion must take place. If the MX-1 is fed a video signal is not just right...well, hopefully I have described why there may be issues such as what you're describing surface.
I'd like to help. If I were you, I would start at the most basic and cleanest set up (short cables lengths, only one or two devices connected) and look for problems. If everything is OK, add a device and test again. It's a pain, but continue until the problem resurfaces. Then replace the last component added and retest. Does the problem go away with the replaced device? If the problem goes away, great. You've found what needs to be replaced. If the problem resurfaces, try eliminating one device or cable and test again. Hopefully you will be able to narrow down the culprit and find a solution.
Try this: How does the MX-1 test with only 6' shielded cables (camera to MX-1, 6' VGA to the scan converter, 6' shielded cable from the scan converter to the MX-1), no splitting of wires, and a different scan converter?
