Alpha Pack 2 - DMX problems

[lbird08]

I have a 3 channel zero88 alpha pack 2 running 2 par battens. I want to control it via DMX using an avolites Pearl.

DMX runs from the desk through a demux, into one dimmer to power some pars, then into the alpha pack and then out to another dimmer. I have full control of everything on all of the dimmers and evrything from demux, but not the battens on the alpha pack. The LED flashes slowly, which if im correct, means there is a fault in DMX somewhere?

I have removed the alpha pack from the line and everything works fine. When it is in the line, everything works fine apart from that!

Address has been checked time and time again and is all ok.

 

Any ideas??

 

Thanks

 

Lawrence

[johnhuson]

You're correct a flashing LED does indicate errors/bad data.

 

Have you tried moving the Alphapack round in the DMX chain i.e. first device or last device? Might not make a difference but worth a try, DMX can be strange when it goes wrong. Have you also tried just the Alphapack on it's own connected to the desk.

 

Also are you using a terminator? If not give that a try. It could be a cable fault which the rest of the chain can cope with but not the Alphapack, adding a terminator would likely show this cable fault up further as the rest of the chain would probably start acting strangely. Or it could be reflections on an unterminated line that are only effecting the Alphapack.

 

EDIT Another thought, it could be the DMX refresh rate of the Pearl is to fast/slow for the Alphapack but the rest of the chain is coping fine. You can adjust the refresh rate using option 13 in the User Settings menu.

[peter]

Hi Lawrence

 

Is your Alphapack 2 a very early one? The first batches of Alphapack had a known issue with the DMX Break Time from a Pearl - this was resolved in firmware in January 2003, so these would have to be very early units to be affected. You can check the software version by following these steps:

 

Power Off the Unit

Set the DMX Address to Position 0 (Start Address 001)

Power On the Unit - if the DMX LED briefly flashes on power up, then the firmware is the old (non-Pearl compatible) version.

If the LED doesn't briefly flash, try setting the DMX Address pot to Position 1 (Address 004) - if the LED briefly flashes then the firmware is the new (Pearl compatible) version and your problem is likely to be a cable fault or elsewhere in the system.

 

I hope this helps - if your pack has the old firmware, your best bet is to call Keith Rogers at the Zero 88 office (01633 838088) and discuss getting your units reflashed.

 

Kind Regards,

 

 

 

Peter

[johnhuson]

Is your Alphapack 2 a very early one? The first batches of Alphapack had a known issue with the DMX Break Time from a Pearl - this was resolved in firmware in January 2003, so these would have to be very early units to be affected.

If this is the case, presumably this could also be resolved by adjusting the break time on the Pearl which is exactly what the setting I discussed above does. Although it's a good idea to get the firmware updated this could be a quick short term fix to the problem.

[danjshelton]

Google is you're friend, as was I to someone a few years ago with the correct answer, see here (post 9 has the answer for the Pearl).

 

To slow down the DMX rate enter into the user settings, and it is on this page. As I said in my post a few years ago we found that 161ms was the fastest speed we could get the desk to output and still get the Alphapacks to respond.

 

Cheers

 

Dan

[lbird08]

Thanks for the suggestions guys. In terms of updating the Firmware, I dont think this would be an option as only hired the kit for a week and need it to all start working for 1st performance at 7pm tomorrow!

I am running mac 500s and 250s from the desk aswell - if I change the speed of the DMX, will it affect their performance? (they are on a different universe). On the same universe as the alpha pack I have 2 other 6 channel dimmers and 3 other analogue 6 channel dimmers running via a demux.

 

Thanks alot!

 

Lawrence

[johnhuson]

The setting does effect all universes but 161ms is not that big a drop from default break time so it's unlikely to have any effect on your MACs but the only way to find out for sure is to give it a try. It's certainly not going to damage anything.

 

If you've hired all of this kit and your still having problems then speak to the hire company ASAP and see if they can swap the dimmer for something else, or offer you another solution. They should be the ones sorting the problems out for you, to be honest I'm amazed they've not come across this themselves.

[lbird08]

Ok, I'll give it a go and see how I get on!

Thanks for your help

 

Lawrence