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Leitch 6800+ / VSD6800+ no signal

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Aleksander Steffensen
Leitch 6800+ / VSD6800+ no signal
on Dec 2, 2011 at 12:28:05 pm

Hi!

I bought an unopened Leitch 6800+ frame with 9 VSD6800+ SDI DA cards in it. I'm having some problems with it, and I was hoping that someone here could help me find out what's wrong.

I'm feeding it with an SDI signal from a Pro-Bel Halo router, through a jackfield. I have tested the signal with other devices to make sure that there is actually a signal going into the VDA, but for some reason, it does not recognise any signal. I've tried several different cards, and they all have a red light indicating no signal, and the + Pilot Lite control application indicate no signal as well. Is it possible that this is due to the fact that I am not (yet) sending genlock to the 6800+ frame?

Thanks in advance

Aleksander Steffensen
Steffensen Multimedia


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Jeff Hartman
Re: Leitch 6800+ / VSD6800+ no signal
on Dec 9, 2011 at 10:36:32 pm

The VSD-6800+ distribution amplifier doesn't use genlock, so not having it feeding the frame isn't the problem. This card is strictly a standard definition DA, and tops out at 270 megabits per second -- if you try to run HD-SDI (1,485 Mb/s) through it, you will get exactly the result you describe.

Jeff Hartman
Engineering Project Manager
Newport Television, Northeast


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Aleksander Steffensen
Re: Leitch 6800+ / VSD6800+ no signal
on Dec 11, 2011 at 2:15:26 pm

Hi Jeff!

Thank you for the answer!

You might be right when you say that the cards do not use genlock, but the rack frame certainly has that option. The signal I run through the VDA is not HD-SDI, it comes from the Panasonic AG-MX70 switcher through the Pro-Bel Halo, which both are SD. As far as I know, the MX70 SDI board is SMPTE 259M-compliant. Any other suggestions as of why this does not work?

Aleksander Steffensen
Steffensen Multimedia


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Jeff Hartman
Re: Leitch 6800+ / VSD6800+ no signal
on Dec 12, 2011 at 5:33:54 pm

[Aleksander Steffensen] "You might be right when you say that the cards do not use genlock, but the rack frame certainly has that option."

Indeed it does. This is used for cards like the VFS frame synchronizer and the ENS encoder / synchronizer... and possibly also the DARS reference generator, though it's been several years since I installed one of those.

As my post later in this thread observes, the problem is most likely that Leitch tends to assign connectors based on looking at the front of the frame -- so the input is on the upper right, if you are looking from the back.

Regards,

Jeff Hartman
Engineering Project Manager
Newport Television, Northeast


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Bob Zelin
Re: Leitch 6800+ / VSD6800+ no signal
on Dec 11, 2011 at 11:23:56 pm

you really need a SDI waveform monitor or SDI TV (at least !) to troubleshoot this. Take the cable going into the Leitch DA, and stick it into the waveform monitor (or TV) - do you see an image ?

Now, put this cable into the input of the da. Take a second cable and come out of the DA, and look at this on your waveform monitor (or TV) - do you see an image ?

If you do not, one of two things is happenng -
1) the chassis is defective (because all the DA cards are all not broken)
or
2) you are not actually plugging the signal into the Input of the DA. I don't remember the back of this Leitch chassis, but many are unmarked (for input and output) and without the manual, it is difficult to identify which of the 8 jacks is the input to the DA (or other module).

Bob Zelin



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Aleksander Steffensen
Re: Leitch 6800+ / VSD6800+ no signal
on Dec 11, 2011 at 11:31:24 pm

Thank you Bob! As I said in the first post, I know for a fact that the input signal is there, as I have tried feeding it to other devices (including Ultrascope). I can't remember if I've tried to feed the output from the DA to UltraScope, but I know that there is no image.

It would be weird if the chassis is defective, as it was brand new, never opened. It might be more likely that I have connected it to the loop O/P instead of the SDI I/P, though one should think that the I/P is the left connector, and the loop O/P is the right one... I'll have a look at it anyways, you never know.. :) Thanks again Bob!

Aleksander Steffensen
Steffensen Multimedia


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Jeff Hartman
Re: Leitch 6800+ / VSD6800+ no signal
on Dec 12, 2011 at 5:21:44 pm

[Aleksander Steffensen] " It might be more likely that I have connected it to the loop O/P instead of the SDI I/P, though one should think that the I/P is the left connector, and the loop O/P is the right one... I'll have a look at it anyways, you never know."

Aha! The VSD/VSE6800+ card's input is the upper right connector, and there is no loopthrough. One thing to remember about most Leitch stuff of this vintage is that the connectors are generally organized to be in order from the front of the frame -- so if you're looking at the connectors from the back, you will see
( N/C ) (Input)

(Out 2) (Out 1)

(Out 4) (Out 3)

(Out 6) (Out 5)

(Out 8) (Out 7)



Regards,

Jeff

Jeff Hartman
Engineering Project Manager
Newport Television, Northeast


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Aleksander Steffensen
Re: Leitch 6800+ / VSD6800+ no signal
on Dec 12, 2011 at 6:05:56 pm

Haha, really? Wow... I suck at diagnostics. I'm heading over to the control room tomorrow morning, I'll try it then, and hopefully it will work just fine. I can't believe that I didn't even think of just plugging it into the other connector - especially when the outputs go from right to left. Thanks Jeff! Lesson learned :)

Aleksander Steffensen
Steffensen Multimedia


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Aleksander Steffensen
Re: Leitch 6800+ / VSD6800+ no signal
on Dec 13, 2011 at 11:11:51 am

Ok, so I did what you said, and it works just great! Thank you very much for your help!

Aleksander Steffensen
Steffensen Multimedia


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