Vidiot key knobs not working

First post here. I’m afraid that my question will sound stupid as i’m a total noob. But I have the same setup as indicated in the vidiot manual : luma out to screen 1, colorizer out to screen 2 and a camera pointed at screen 1 connected on the camera in port.
when i turn the key knobs nothing happens. They already worked at least once but since that session, nothing happens on the the luma display or on the colorizer display …
The switches that can be set to key, are set to key.
I don’t know if there is a link but another weird stuf is that the luma out screen is grey even with the brightness control and cv level at zero, is it normal ?

Any ideas ???

Thanks !

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Hi @Matthys . I’m glad you decided to ask your question. If you’re thinking it, chances are a bunch of other people are wondering too. The grey screen with zero brightness does sound strange, but it could be setting-related.

The first thing to check are the default settings (brightness/contrast/detail knobs to 50% point, CV levels to 50% point, two-position Mode switches to the left (Positive values). The Loop switch should be in the down position, otherwise the camera data won’t make into the device through the input. (If you try all this and things still aren’t working, try the Loop switch in the alternate setting – we’ve seen at least one Loop switch installed backwards). Set the Luma preset dial to its left-most position, the Video input setting.

What are you seeing at this point? If it’s still just grey output from the Luma out, do brightness or contrast knobs or Mode switches make any changes to the output signal? If not, does selecting a preset like Noise lead to any changes?

Once we get the device outputting normally again we can get to those Key knob issues.

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Can you take a quick video to demonstrate what you’re seeing? That would be the best thing to help me understand if you’ve got a problem with your unit or if there’s something you’re not understanding yet. It’s an intricate signal path for a beginner and does take some getting used to.


I had some weirdness the other night that sounds very similar. Everything was set up and tested at an event, and i turned everything off until the set started, and then just before playing, i turned things on, and all the luma knobs stopped working, and everything was a light grey. turning it on and off a few times brought things back (the first couple of times, it came back for a few seconds and then went grey again), i noticed the unit was getting quite hot, or at least hotter than I remember it getting at home.

Sorry this is a bit anecdotal. If it happens again, i’ll document it and share my findings.

Thanks for answering :slight_smile:

So i did what you said @48HourVideo (all knobs in center position) it wasn’t working, still this weird grey luma output (to be more precise, the brightness and contrast knobs work but still grey instead of black background) and nothing hapenning when turning the key knobs. I tried to put the loop switch up and did several power cycles like @Polite did. And now it works !!! even with the loop switch off… I wanted to send some videos but i can’t get the explained issue again…
It seems that both problems (grey luma + key knobs not working) are linked … Also i just figured out that the diamond and circle modulation source now work perfectly, (i found they had a great lack of contrast and were barely visible in most cases with the grey luma and key knobs not working issue).

Do you have any ideas about what’s going on ? And/or how to avoid the issue ?

Thanks for your help !!! :slight_smile:

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I’m still pretty unclear on the issue. Can you show me a quick video or screenshot, showing all settings on the front of the unit, and what the output looks like? Details on any external source or display you’re using would be helpful too. Note that nothing will happen with the Luma Processor unless you have an external source plugged in (you could also patch a source like a shape out from the front of the unit, to the rear Luma input 1V/3.5mm jack.)

Hi @creatorlars
thanks for answering :slight_smile:
Ok i tried to connect the circle output to the luma input. Set all the knobs a 12h and the switches to key.

Now the luma output to a lcd screen :

And the colorizer output to a crt tv :

When I tweak both of the key knobs nothing happens.

Sometimes the problem is solved after some power cycles but it comes again after some other cycles.

(Sorry for my English)


In fact it seems to work normally for a second at every powering up and then goes in this strange “grey no key” mode most of times

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Yes that does seem quite weird, and probably power entry related. It’s uncommon for an analog device to work for a second and then “crash” like that. You’ll want to request an RMA at your convenience by e-mailing

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