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One way diodes?


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#1 Iain Baird

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Posted 09 June 2006 - 07:10 PM

I use a sony camcorder, the smallest they make - the model excapes me, as my onboard recorder. The only issue I have with it is that the input and output connection on the camcorder are the same (the unit has an internal switch) , and it's unchangable default start up is in Camcorder mode. This results in a second signal entering the video line. It's a pro III lower unit. A couple of clicks later and the camcorder goes into record mode then it's a receiver instead of a transmitter and the double image (camcorder feed + camera feed) is gone. Even though I have to switch the camcorder over anyway the one moment that the signal gets messed up always seems to send video village into a panick. Has anybody had any experience with this sort of issue?

I'm thinking of installing a zener diode to stop the second image.


IAIN BAIRD
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#2 Eric Fletcher S.O.C.

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Posted 09 June 2006 - 09:37 PM

It will drop the signal voltage, just use the video input switch on the left side of the battery rack.
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#3 Iain Baird

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Posted 10 June 2006 - 01:33 AM

That swich doesnt stop a signal from going the wrong way. It only shuts down the feed from the live video and isolates the recorder output to the monitor. If your recorder input output is the same wire then both signals use the same pinout on the 5 pin lemo. In rec mode that switch will still et the signal from the camcorder go the wrong way.

Iain Baird


i'm not sure if I should be insulted by your solution or not, what does the 12/24 switch do?
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#4 Eric Fletcher S.O.C.

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Posted 10 June 2006 - 01:37 AM

That swich doesnt stop a signal from going the wrong way. It only shuts down the feed from the live video and isolates the recorder output to the monitor. If your recorder input output is the same wire then both signals use the same pinout on the 5 pin lemo. In rec mode that switch will still et the signal from the camcorder go the wrong way.

Iain Baird


i'm not sure if I should be insulted by your solution or not, what does the 12/24 switch do?



If you are flying the transmitter on the bottom of the sled then you transmit the output of the recorder during playback. The switch disconnects the Upper D-Box video input.

Like I said it works fine for me and I have been using a deck that internally switches video for 10 years.
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#5 Iain Baird

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Posted 10 June 2006 - 12:59 PM

The problem that I have Eric is when I first turn on the sled, with the DB III switch set to REC, both the camera and the camcorder send an image to the monitor and transmitter, because they share the same video line. I have to then turn the camcorder over to LINE INPUT to turn off the camcorder output.

If I turn on the sled, I quickly switch the camcorder over and no one is the wiser, but assistants don't always know how to do it. It leads to head scratching and DP's yelling that the monitor is all messed up.

I was hoping there was a way I could put a one way diode on the input and use the pin 5 on the plug as the output. Then even if the camcorder was playing the only way a signal could get through would be when the switch is in PLAY.


Iain Baird

Toronto, ON
presently in Dublin
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#6 Matt Petrosky

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Posted 10 June 2006 - 02:46 PM

The diode will introduce other problems including blocking your ability to playback on the steadicam's monitor. You could change the video switch over to a double pole double throw (DPDT) using the the additional switching side you gain (from the stock SPDT) to cut the video signal off from the recorder. Wait a sec, actually that won't work because then you will have blocked the signal and nothing will be recorded unless you are in playback mode. I would just consider adding a simple SPST or DPST switch that cuts the 5-pin's recorder signal off from the rest of the rig. Make it a habit when you power down to cut the video off. Of course the best solution is to have a recorder that remembers the last position it was in and boots up in recorder mode.

This is a similar problem that the Supacam suffers from. The Supacam has a separate input and output, but the output is ALWAYS active, so the deck is always sending a video signal into the rig. The ideal steadicam recorder would have a single input/output that intelligently switched and remembered the last setting. When you are in record mode on the deck it would automatically become an input and when you played back it automatically switch over to an output.

Good luck with it,
Matt
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#7 Iain Baird

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Posted 10 June 2006 - 05:50 PM

The best solution would be the option to change the default in the camcorder to input. Then everytime the sled is powered down, when powered back up it would not go back to camcorder mode. But unfortunately the camcorder has no such option. When in the on position and when it first gets power it sends a signal into the video line.

At the moment Pin 5 remains unused, I've ordered some zener diodes with a 3.5 v resistence rating. So the worst that can happen is that I have a failed experiment, with a 5 euro cost ( thankfully I can take the hit ) . I'll update further.


IAIN

On another note Eric I am sorry if I sounded sarcastic with my 12/24 comment.
Knowing the wiring of the sled very well, and having done lot's of personnel wiring mods to the unit, I felt like the suggestion was rather basic, and obvious.

Iain Baird
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#8 Charles Papert

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Posted 10 June 2006 - 07:05 PM

Matt and I spent a long and rather painful day trying to make the Supacam work through this particular nightmare, so far no real solution...Iain, if you can make this work, we are all ears.
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