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Monitor signal going out through post.


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#1 Michael Wilson

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Posted 03 September 2015 - 02:12 PM

Lately I've been getting signal loss in my monitor through the sled.  Its been really random as of late manifesting in different variations so its been hard to pin down.

 

I have the MK-V sled with version 2.5 electronics.  And a marshall vlcdstx651.  

 

A friend helped me test the connections and it seems like everything is good at all the ports.  He thought it might need a new DA.  

 

Thicker cables from camera to sled seem to help but it still goes out from time to time.  Walkies sometimes trigger it.  Some days its totally fine.  Its just been so strange and I've done so much testing I could write for days.  

 

Any thoughts?

 

Also it went out the other day, just as they called action, and I just decided to go with it.  I've never heard a bigger reaction from video village in all my years of operating.  "That was awesome!!!  Nailed it!!!"  So maybe its a good thing.  


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#2 Libor Cevelik

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Posted 03 September 2015 - 02:22 PM

in what point u lose the signal ? when u check the connections is the sled horizontal or vertical ? it maybe loose cable/connector problem and then in movement or acceleration it loose the connection .. maybe ? 


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#3 brett.mayfield

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Posted 03 September 2015 - 04:24 PM

i used to have walkie interference when using spaghetti cables for teradek etc. so i dont touch em anymore.

have you recently fully extended your sled? i started having problems with one of my 2 HD lines on my cinelive after flying a studio Alexa with some Hytron140s fully extended. my sleds never been the same since. neither have my orifices.


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#4 Michael Wilson

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Posted 03 September 2015 - 05:36 PM

I lose signal normally when docking/undocking, switching to low mode, touching the cable or adjusting the monitor or just randomly.  We had it vertical when testing the connections.  So that may be an issue.  We opened up the post cable at the top and everything looked good.  

 

Yikes Brett.  Might want to get that checked out.  Haven't had it fully extended recently.  


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#5 Marty Smith

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Posted 03 September 2015 - 05:44 PM

Michael,

 

I have an MKV rig and it was suggested to me from a friend (who also operates a similar rig) that the early versions of the electronics were more susceptible to interference from two ways - apparently the shielding in the post cable isn't the best and gives you that intermittent response you are experiencing.

 

I upgraded the electronics in my rig to the V4 and haven't experienced any issue.  I'm no expert - but it may be something worth considering.  Particularly if the connections all check out.

 

All the best


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#6 Mark Stitzer

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Posted 03 September 2015 - 06:57 PM

I have an MK-V Evolution sled and have experienced monitor signal drop too.  My electronics seem to be very picky with the video cable used to feed the sled.  When using some old or cheap cables (don't ever buy a monoprice BNC) I will routinely have the signal drop out completely requiring me to power cycle the sled to get picture back.  Other times, the image will flicker a bit and slowly get darker to the point where the monitor is only about half brightness.  I can reset it by disconnecting and reconnecting the video line from the camera to the sled.

With a good quality cable, It works fine all day.  I've checked all my connections on those other cables and they are solid and carry signal directly to a production monitor just fine.  Seems to me that maybe the MK-V electronics are more sensitive to cable construction and impedance.

 

Mark


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#7 Michael Wilson

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Posted 04 September 2015 - 01:12 AM

Hey Marty,

 

MKV sent me new electronics a few years ago.  They said they had upgraded power and shielding however they weren't the v4 version.  And they've worked well for quite sometime.  And now they are not.  So a repair might be better than upgrade cost wise.

 

J box looked good.  Solder and voltage tested

Top of post cable looked good as well.

I believe we tested voltage on the hdsdi line from top of post cable to distro(bottom of sled)  that was fine but probably would have exhibited issues if knocked around.  We also tested with the sled powered off.  Fine but would drop out from time to time with weak cables.  Bigger cables better but would still happen.  A head scratcher.

 

I think I'll have Terry West look at when I get a chance.  


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#8 Marty Smith

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Posted 04 September 2015 - 01:29 AM

Sorry to hear that Michael - and apologies for telling you something you already knew!!

 

Good luck, I'd be interested in hearing the outcome.


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#9 Michael Wilson

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Posted 22 September 2015 - 03:44 PM

hey all,

 

Just wanted to share a little update.  I've been using thick cables and cut out the 90 degree connectors.  I've had no signal drop out on the last few jobs I've done.  Even with walkies right next to the sled.  Lovin life now.  


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#10 Tuomas Viitakoski

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Posted 09 November 2015 - 05:19 PM

Hi Michael,

Didn't see your thread until now but glad that you got it working.

The connectors'/cables' shielding is very normal issue. If you experience signal loss make sure all your cables have a solid center conductor (makes stiffer cables), copper braid shield and two-layered foil.
Attached File  shielded coax.jpg   10.46KB   3 downloads
And then, no matter how thick the BNC cable is but if the connector is lacking insulation it will most definitely cause this issue especially if the center conductor is exposed or missing proper shielding.

Also 50/75Ohm BNC adapters (right angle adapters, BNC extensions etc) have been to be blaimed on some occasions.

Once I had a HD-monitor that was working poorly with a regular BNC but then I wrapped foil (from 3G coax-cable) around the soldered panel connector and now +45 meters works fine.
Poorly shielded BNCs and coiled cables are known to work as an antennas and being next to powerfull transmitters might mess up your signal.
A proper cable with proper connectors (doesn't have to mean stiff and bulky) or a little fix with foil will make your day a lot better and doesn't cost much.

Best,
-Tuomas


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#11 Sung-young Park

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Posted 20 November 2015 - 07:55 AM

Hi Micheal

That problem is absolutely Marshalls.
You need to change signal process board in your 651stx. Your 651stx might lost signal almost while you docking, If that borad is bad. And sometimes undocking and just power rebooting.

Contact to Marshall!
Cheers
SY Park
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#12 Sung-young Park

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Posted 20 November 2015 - 07:56 AM

Hi Micheal

That problem is absolutely Marshalls.
You need to change signal process board in your 651stx. Your 651stx might lost signal almost while you docking, If that borad is bad. And sometimes undocking and just power rebooting.

Contact to Marshall!

Cheers
SY Park
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