Oversensitive mac 2000s

[Ike]

I've just been working with a rig containing a lot of strobes and mac 2000s on hard power. When all the strobes fired it caused a slight brown out which in turn caused half the macs to reset. We ended up running the macs from a different power source however life would be a lot easier if this didn't have to be done for the rest of the tour. Does anyone know of a "secret trick" to prevent the macs resetting so easily short of fitting a load of capacitors across the psu output? I'm assuming its the drop in the LV supply to the board and not a drop in the mains directly that's causing the resets??

 

Oh yeah, and not firing so many strobes at once isn't possible...apparently!

 

Thanks,

 

Ike

[AndrewR]

Dont know any tricks myself, but would be easyer if you could provide the number of mac 2000's and the number (and current demands) of the strobes. Along with the rating of supply you were using.

[paulears]

The thing is it isn't the firing, but the recharging after it. If all the strobes draw full current that is sufficient to reset the macs, I'd have thought the protection on the distro would have tripped out. If the sudden surge is within the breaker limits, why would the macs be suffering what does sound like a sudden supply low. Can you meter or display the mains when the resets happen? Maybe you can see the level the supply drops to? Is there a chance the supply to the strobes simply isn't sufficient?

 

Plenty of questions - tell us a bit more?

[AndyJones]

Because of the addressing on the strobes, it is right next to the DMX reset value, (im not sure of the exact values) so if ever you put them inot strobe and set the strobing to fast the DMX moves into the Reset value hence the reset. There is a feature on the lanterns were you can turn this off, I cant remeber off hand, but it is done on the fixture, have a look through the manual, there is a section with all the different controls.

 

Hope this helps

 

Andy

[zonino]

andy, I may be misreading you but I think your talking about the reset function on the mac, whereas the OP is talking about a power induced reset,

 

is running a few of the strobes off a seperate source a viable alternative? or say X macs n Y strobes off one source, and the other X macs n Y strobes off another? this way your cabling requirements are about the same, rather than running lots more for seperate strobe feeds

[paulears]

Just a comment for andy - unless the strobes are on the same DMX address as the macs - I don't follow your point?

[Ike]

Sorry for the quick reply but I'm a bit busy today.

 

The problem we have is that the strobes we are using (atomic 3000s from martin) have a peak current draw of 33A however as we are using thirty six (yes 36!) of these providing enough headroom to prevent a brownout when all these are recharging as well as all the dimming, macs etc is pretty difficult. The irritating thing is that the macs seem to be a lot more sensitive than just about anything else we can find, a back of a beermat calculation last night showed that the brownout only lasts a cycle or two at the most a a couple of measurements shows the voltage doesn't drop much below 200RMS. With the short duration we have had no problems with trips etc.

 

Thanks for your time,

 

Ike

[peter]

As you say, the Atomic 3000's can cause a voltage drop which is enough to cut out the 5v supply in most fixtures, causing them to reset. One option if you need to use the fixtures for a long duration is to switch them to low power mode. More info here.

[Ike]

Thanks! Really wish I had googled it a bit better.

 

Strangely enough it seems only to be macs that are affected. We did a test with a couple of vari*lites and they were fine, as are our demuxs, DMX splitters etc.

[fraggle]

Ike,

 

although its quite likely you are suffering from brown out problems, it is possible to get glitches between MAC2ks and Atomic 3000s attached to the same DMX line, it may be worth you trying to seperate the data feeds to the MACs and the strobes.

 

Although Atomic 3000s can draw up to 33A it varies massively with the mode you are using them in and flash rate / duration, I generally estimate them at around 10A average when I do my clacs (for arena size rock shows) and although this is obviously just an estimate I usually seem to get pretty close.

 

Its also worth checking you have a good (and fully rated) neutral connection on your supply, as this can also cause you problems. You don't mention whether your mains is 3 phase or single either.

 

Hope some of this helps.

 

F.

[paulears]

Is it me, or is this just a tiny bit crazy? Two Martin products which annoy each other? Sounds like they should have produced some kind of psu mod kit and shipped them around the dealers. It isn't a budget piece of kit that has a power problem, it's a major piece of kit. Strobes and movers together isn't exactly rare.

[b1nuzz]

I dont know if anyone saw the recent Faithless tour, but there was nearly 80 mac 2000s some wash some spot and nearly 40 atomic 3000 strobes. They all worked pretty seemlessly with each other. No problems at all.

[AndyJones]

Sorry guys, I misread the post, I thought he was on about the mac 2000 shutters (strobing) sorry!

[Pete McCrea]

I dont know if anyone saw the recent Faithless tour, but there was nearly 80 mac 2000s some wash some spot and nearly 40 atomic 3000 strobes... No problems at all.

Did you see how they were doing the distribution of Power and DMX?

 

I'd hazard a guess and say they were using a large supply, and had divided things up such that the Strobes and Macs were on different supplies to minimise the problems. They might even have ahd the same issue as the OP has, excpet weeded it out in the rehearsals.

 

I must admit that I'd have thought that Martin would have built the PSU so that it could take the alterations in supply voltage a bit better.

[Ike]

Low power mode helped but we still had a problem with a couple of fixtures so we have resorted to a separate supply for the macs. Thanks Fraggle, I tried separating the DMX feeds but that didn't seem to affect it. We are using them at full power and there highest flash rate for a couple of seconds so this is where the problems tend to kick in.

 

Luckily this was all found in rehearsals so no real harm done. If its only the 5V supply that has problems wouldn't a retro-fitted voltage stabiliser to the psu o/p do the trick. I can't see the price being prohibitive when you take into account the price of the fixture.