ZR33 - Non linear output

[Neil Hampson]

We have had reason to start using our brand new 'Spare' Jem ZR33 Hi-Mass smoke machine (see other thread about coffee machine pumps) One property of the old machine was that at about 12-15% the unit would produce a very small amount of faog and as the level increased the output obviously became denser to produce a full on Smoke. We used to use this property when only a tiny amount of smoke was required, almost as you would use a hazer.

 

However the new machine refuses to do anything like this, the unit does not respond to DMX until about 15% (or the on-board analogue, it doesn't matter), and then almost like a switch, produces quite a large volume of fog. The effect is quite dissapointing, unless you are trying to simulate the arrival of a steam train.

 

Onto the question: Is there anything we can do to get a better low level response from the unit, an internal adjustment etc. or do you think this is possible grounds to return the unit? or is this perfectly normal behaviour for a ZR33 and the 'old' is actually the one that is defective.

[gareth]

Sounds like your ZR33 might have a problem. We have three of them, and they all have a reasonably useable linear response to the level of their control channel.

[Matt Cowles]

It could be as simple as adjusting the pump output pot on the main PCB but it has been a while since I had my head inside one of these so I may be talking nonsense. I'd ring Martin service on 01622 755442 and speak to Stuart or Jonathan, they will be able to suggest a solution for you.

 

EDIT: By the way the "old" unit is the one that is working properly, you should definately have a useable linear output

[stuart.t]

The potentiometer used to control pump speed is located on the main PCB just above the top spade where the thermocouples plug onto. The potentiometer inbetween these two spades is for heat controll and must not be adjusted.

 

To correctly set up pump speed the ZR 33 has to be set to level 2 and start to pump smoke from the unit. The output should just start to trickle out, if the output is flowing out at a high volume or no output at all adjust the potentiometer so the pumps speed is adjusted.

[Neil Hampson]

Thanks for that info Stuart, I'll give it a go nex time I'm in the theatre.

Just a point of interest, why do you set it not to do anything until 20%, rather than 5% or so?

Our older, now repaired ZR starts to 'Haze' at about 10-15%

[stuart.t]

The reason for setting it at level 2 is because if you are to set it at level 1 or lower then by the time you get to level 10 the pump will be runnign too fast for the block to handle and could cause the unit to spit hot fluid or make the smoke wet.