zero 88 Betapack 1 and Strand s72 demux problem

[j.cort]

Hello, I have recently purchased a betapack 1 and a strand s72 demux separately, the problem I am having is that the light output is flickering, I have got it on the setting of plus 10v, I have tried different settings and they all seem to have the same results, any ideas for help? Thanks

[boatman]

Hello, I have recently purchased a betapack 1 and a strand s72 demux separately, the problem I am having is that the light output is flickering, I have got it on the setting of plus 10v, I have tried different settings and they all seem to have the same results, any ideas for help? Thanks

 

It sounds like it could be a bad ground connection on the cable. Did you buy a ready-made cable or roll your own?

[j.cort]

The cable from the demux to the dimmer? It was ready made

[Don Allen]

Do you have a good quality DMX cable going to the demux DMX input ?

Have you terminated the DMX cable ?

What desk are you using, there may be DMX refresh timing issues?

[j.cort]

I have a 5p-3pin adapter, yes I have terminated, and I have used 3 different small desks, with the same results

[PaulDF]

With the demux unplugged from the betapack, do you still get the flickering outputs if you turn the test knob on the betapack?

 

Looking at a pic of the unit on the web, it looks very similar to the Botex / Showtec / Elation 72 channel demux units bar the lack of 3 pin XLRs.

Can you bell out your wiring - if it is the same as the Botex ones the pinout is as follows:

 

Ch1 = Pin 13 (to Pin 1 on Din)

Ch2 = Pin 25 (to Pin 2 on Din)

Ch3 = Pin 12 (to Pin 3 on Din)

Ch4 = Pin 24 (to Pin 4 on Din)

Ch5 = Pin 11 (to Pin 5 on Din)

Ch6 = Pin 23 (to Pin 6 on Din)

Ch7 = Pin 10

Ch8 = Pin 22

Ch9 = Pin 9

Ch10 = Pin 21

Ch11 = Pin 8

Ch12 = Pin 20

Ch13 = Pin 7

Ch14 = Pin 19

Ch15 = Pin 6

Ch16 = Pin 18

Ch17 = Pin 5

Ch18 = Pin 17

Ch19 = Pin 4

Ch20 = Pin 16

Ch21 = Pin 3

Ch22 = Pin 15

Ch23 = Pin 2

Ch24 = Pin 14

Earth = Pin 1 (to Pin 8 on Din)

[j.cort]

Works fine on the test function and on the analogue controller, I am not sure about the wiring layout from the demux, but it is the 25pin to 4 8pin din cable that stage electrics supply,

[PaulDF]

Next thing I would do is to bell the cable through to make sure it is made up correctly. If you look at the back of the demux there ought to be a legend saying what channel comes out on which pin of the 25 way D, very likely as I listed above.

The betapack end is pretty simple with the din plug, pin 1 is ch1, 2-2, 3-3, 4-4, 5-5, 6-6, 7 not used, 8 gnd.

[ianknight]

The Trancension demux (and the Strand is/was a badged version of the same hardware with more input connectors) "suffers" from having a slightly non-standard pin configuration on the outputs and Strand used to include some adaptor plugs that handled the pin swapover which you will need to use unless you know the din to D cable doesn't need it.

 

I've generally found these units reliable however the outputs on the Demux drive direct from the Op amp outputs with no diode protection (certainly the early ones didn't), so you need to be careful with shorting pins together, connecting racks which have two different polarity's of desk supply I.e one supplying neg and one positive and drawing too much current from the outputs (Mini 2's foreshorten the chip life - had that one as well!). It would be worth checking that you have a good mains earth at both Demux and rack and that it's the same Earth if possible (some venues split the demux from dimmers to use existing wiring and end up with different potentials on the earth) as this can cause most of the headaches with this sort of unit - questionable earths.

[PaulDF]

I don't think the showtec one I have has diode protection either as turning the test knob on a betapack with the din connected results in the channel coming on dim hence a good reason to unplug first. A betapack 1 will accept 0 to +10v or 0 to -10v for control, it has a signal converter on the input that passes +ve and converts -ve signals (or vice versa, don't have the schematic to hand but doesn't really matter)