DMX puzzle

Our church had a lighting hit several months ago. It took out a Fleenor splitter and 2 of our 4 Autoyokes with SourceFour fixtures. Had boards and/or units rebuilt.
The autoyokes are hung from ceiling - 2 on each side of booth. Each side has the 2 units chained and fed from an existing dmx recptical. Both units that went out were first in line.
I tested each repaired unit by connecting it directly to our ETC expression III. Both worked. We then then rehung units - 30 ft up with a ladder. On one side both untis work. On the other side the first in chain (repaired unit) goes thru home sync but wont respond to DMX. The second in chain works. By removing jumper to second unit, first unit starts working. By sending DMX first to second unit and then to first (bypassing first unit's DMX ouput port) - same result first unit wont work second one will.

No they are not terminated. No as built wiring diagrams and we have several hunded fixtures. DMX wiring appears to be cat5.

Even with all the above - I can't explain why it used to work and now doesn't.

Plan to recommend we run real DMX cable from splitter (have unused port available) and daisy change just Autoyokes with terminator.

Any ideas to get unit going until rewiring would be appreciated.

Thanks

Interesting problem.
I suspect the first's DMX reception circuity has lost either D- or D+. When it's the only thing on the line, it works with just one data line and common. When there is more load on the line, it can't differentiate the signal.
I'll point someone from City to this thread.

Did you use the same cable to test on the ground as you did in the air. Sounds like it’s just a bad cable. Also what DMX smoothing options do you have enabled. Maybe the 2nd fixture is set to a different smithing or processing the values different. The ideal thing is what you suggested and just run a second line to the unit not working and see if that does it.

Hello, that is an interesting problem. My name is Jannelle and I am tech support from City Theatrical. Have you tried any of the above suggestions? Or have you made any new discoveries since Wednesday?
If you need further assistance please feel free to send us an email or give me a ring! [email protected] or (201) 559-4233

No smoothing options. I want to get a terminator and try that. Had to take ladder down this is in sanctuary and the room is very active.
We have to schedule when we work and have to get staff together - takes 3 men to handle ladder.

When we install terminator I will replace both cables. If this doesn't solve problem we will install real DMX cable from splitter to units.

Thanks for come backs

Good Morning

Replace 1 thing at a time if you can
Then retest

If you replace multiple items you can't be sure what the bad component is.

I know it's high ladder work but just call it an education exercise.

I have come up with a plan that I think will make all units work. Since the AutoYoke will respond if it not daisy chained, we can run it by its self , Then take its partner and chain it to the other two autoyokes that are working.