MAC 250s

[Matty93]

Hi all,

 

I am new to this forum and I really need you guys help!! I have 4 mac 250s daisychained and terminated along side with a standard rig controlled using the ETC congo. All the macs have correct addresses and modes but they do not respond and the DMX lights are not lit. I gathered that this is because there is a faulty cable somewhere in the link (top quality hired stuff!!) but could you guys walk me through all the scenarios where the DMX lamp would not be lit. Thanks!! :** laughs out loud **:

[franki]

Hey,

check the DMX its more likely a problem with the cables themselves rather than the light. Try replacing the first cables in the chain. :** laughs out loud **:

let me know how you get on. :P

 

Hi all,

 

I am new to this forum and I really need you guys help!! I have 4 mac 250s daisychained and terminated along side with a standard rig controlled using the ETC congo. All the macs have correct addresses and modes but they do not respond and the DMX lights are not lit. I gathered that this is because there is a faulty cable somewhere in the link (top quality hired stuff!!) but could you guys walk me through all the scenarios where the DMX lamp would not be lit. Thanks!! :P

[Matty93]

Thanks! I am dreading crawling round before the focus tomorrow trying to find the dodgy cable!! If I replace it with a good one will the DMX indicator just come on?? Bloody hired cables!! :** laughs out loud **:

[woody74]

...walk me through all the scenarios where the DMX lamp would not be lit.

I believe there's only two: either the LED is burned out or there's no DMX.

 

As to why it's not lit, there's what you need to sort out. Could be a faulty cable. Could be a bad DMX card. Could be a PEBCAC error.

 

Your best bet is to use what you have already: put the DMX feed into the second light the chain and see if you get signal. If not, it's most likely upstream and including the data cable feeding the rig. If so, it's probably somewhere in the first fixture.

 

And of course this all assumes the Congo is patched correctly and is sending signal.

 

-w

[Matty93]

Thank you! All the lamps and DMX is hired so I would imagine that the fixtures work but after what you guys said I am convinced that it is a cable. Not looking forward to tomorrows fun!! Matty

[Joe Bleasdale]

Well will the lights respond to any other attributes pan, tilt, etc?

 

thanks

joe

[nicemms]

Thank you! All the lamps and DMX is hired so I would imagine that the fixtures work but after what you guys said I am convinced that it is a cable. Not looking forward to tomorrows fun!! Matty

 

If its not working and its all their gear, presuming you've plugged it in correctly, get them to come in and sort it!

[Matty93]

Thank you! All the lamps and DMX is hired so I would imagine that the fixtures work but after what you guys said I am convinced that it is a cable. Not looking forward to tomorrows fun!! Matty

 

If its not working and its all their gear, presuming you've plugged it in correctly, get them to come in and sort it!

 

Not sure if I am allowed to say company names here, but they are hopeless!! I would rather do it myself tomorrow!! ;)

 

A concurrent post has been automatically merged from this point on.

 

Just had a thought though I am in a noobish mood!! Surely it must be one of the 1st cables that is bust cos if it was after the 1st lamp then at least the 1st lamp would work right??

[Tomo]

Oh dear Matty! You really are digging yourself a hole here, and after I had such a glowing report from your teachers!

 

Troubleshooting is very simple, but you have to think about everything logically:

 

Step One: Determine the cause(s) by trial and elimination. Experience helps here!

Step Two: Repair/replace the failed item(s)

 

In your case, the simplest thing to do is to eliminate everything except 1 fixture, 1 cable and one DMX source. Does it work?

Yes - Those three components are good.

Add one more cable - does it still work?

No? There's your problem.

 

This basic methodology works for everything. As Sir Arthur Conan Doyle once put it many years ago:

"Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth."

[Matty93]

Oh dear Matty! You really are digging yourself a hole here, and after I had such a glowing report from your teachers!

 

I think you mean technical manager ;)

 

I am having a basic issues day but I think I now understand!! I haven't left that theatre in a month! Basically I just need to go through each fixture and disconnect it from the rest and see if a get the DMX signal led? But my question was surely it must be DMX going to the 1st fixture because if it was after it at least the first lamp would work right! Or am I just having too tired syndrome!!! Aaah my brain is going wrong!! Probs lost its DMX signal!!

[Tomo]

But my question was surely it must be DMX going to the 1st fixture because if it was after it at least the first lamp would work right!

It's likely and worth checking, but there are other possibilities.

 

There could be a short circuit between data pins and/or shield further down the daisy-chain which is destroying the signal

The first fixture might have an internal fault that prevents the signal entering it or passing down the line.

The console itself may not be transmitting DMX.

 

So the first thing I would do is disconnect the downstream DMX from the first fixture and see if the first fixture starts working.

If it doesn't, then it's definitely the first cable, console or fixture - so eliminate one of them and see what happens.

 

I carry a DMX test device with me most of the time (an AL Microscope 3a), to quickly check whether a given DMX source is really working, or that a given receiver is OK.

I've rarely used the cable test function to be honest - I don't often have access to both ends of a cable!

 

(And you're right, I do mean your technical manager)

[Matty93]

But my question was surely it must be DMX going to the 1st fixture because if it was after it at least the first lamp would work right!

It's likely and worth checking, but there are other possibilities.

 

There could be a short circuit between data pins and/or shield further down the daisy-chain which is destroying the signal

The first fixture might have an internal fault that prevents the signal entering it or passing down the line.

The console itself may not be transmitting DMX.

 

So the first thing I would do is disconnect the downstream DMX from the first fixture and see if the first fixture starts working.

If it doesn't, then it's definitely the first cable, console or fixture - so eliminate one of them and see what happens.

 

I carry a DMX test device with me most of the time (an AL Microscope 3a), to quickly check whether a given DMX source is really working, or that a given receiver is OK.

I've rarely used the cable test function to be honest - I don't often have access to both ends of a cable!

 

(And you're right, I do mean your technical manager)

 

Ok thanks!! Why cant it all just work!! When I connect the downstream from the 1st fixture do I still need to terminate it?? To check the the congo is sending signal should I just run a dynamic effect so I can tell when they are working?? Sorry for the questions but I am soooo tired at the mo!!

[Tomo]

Why cant it all just work!!

If everything always worked perfectly first and every time then I wouldn't have a job!

 

More seriously - don't worry about it now. Planning fault finding is generally pointless, as the fault is almost always either really obvious, or somewhere you wouldn't have thought to look.

[Matty93]

Why cant it all just work!!

If everything always worked perfectly first and every time then I wouldn't have a job!

 

More seriously - don't worry about it now. Planning fault finding is generally pointless, as the fault is almost always either really obvious, or somewhere you wouldn't have thought to look.

 

I'm not worrying ;) I dont have much time to do stuff though! (School :) ) Everything else works though ;)

[woody74]

When I connect the downstream from the 1st fixture do I still need to terminate it??

Always. And just to ease my mind, these don't have termination switches on them do they? You're not terminating every fixture somehow...?

 

...should I just run a dynamic effect so I can tell when they are working??

Could work, but you run the risk of getting thwacked in the head if it starts to move when you restore DMX...ouch.

 

-w