SHOWTEC Multi Exchanger fault

[willjam39]

Hi,

 

I am doing a local amdram show, and to take control of their analogue dimmers I use the above unit. Yesterday when flashing through to see what was working I found that the channels were out of sync with no pattern.

 

I have checked the internal patch on my desk is right and the lights behave as expected with the analogue desk. I have also checked the correct polarity and voltage level for the dimmers .

 

Has anyone had experience of a Showtec demux jumbling up channels?

[dmxlights]

Can you post the make and model of the Dimmer packs as I can help us as well.

 

Know you said it works fine with the analog desk. It could be something to do with the patch cable from the dimmer to the Showtec demux.

 

[Brian]

Know you said it works fine with the analog desk. It could be something to do with the patch cable from the dimmer to the Showtec demux.

 

IIRC, the pinouts on the D25 are not intuitive.

[J Pearce]

And critically, the pinout is very different to other demuxes that use otherwise identical cables.

[erik10_4]

As others have said, my first suspicion would be connection between the D25 connector and dimmer packs. I have two Showtec Multi-exchangers (both bought second-hand) which have worked faultlessly with both Pulsar and Zero dimmer packs. The difficult bit when I purchased the first Showtec unit was building the interface cable between the D25 and the 8 pin din sockets as they obviously had to be wired differently to handle the different wiring protocols for Pulsar & Zero dimmers. Have you successfully used the Showtec unit with this brand of dimmer before? Do the dimmers previously interfaced with the Showtec share the same wiring/pinout/polarity protocol as the dimmers you are trying to operate now?

[willjam39]

Hi guys,

 

The Dimmers are Strand Act 6s and the desk is a Strand 520i.

 

I have used the Demux before with the dimmers But on a much shorter time scale so may have assumed any issues were bulb issues as the in venue kit isn't maintained often.

 

The talk of pin outs has reminded me of another symptom which might guide, when channel 2 is selected up on the 520 I get multiple channels on the stage come up.

 

Thanks for the quick responses and hope my answers help

 

Will

[Alan Pickwick]

Hi guys,

 

The Dimmers are Strand Act 6s and the desk is a Strand 520i.

 

I have used the Demux before with the dimmers But on a much shorter time scale so may have assumed any issues were bulb issues as the in venue kit isn't maintained often.

 

The talk of pin outs has reminded me of another symptom which might guide, when channel 2 is selected up on the 520 I get multiple channels on the stage come up.

 

Thanks for the quick responses and hope my answers help

 

Will

Dear Will,

 

Check the switch settings on the Showtec. Set to 10 volts and negative output for Strand.

 

I had a similar random event some years ago when Pin 1 was not making proper contact in the socket.

 

Examine the 25 pin plug for pushed-back pins. The most critical is pin 1, the earth (common return) pin.

 

Try reseating the plug and make sure the screws are tight and even.

 

Next carefully take off the shell of your 25 pin plug and look for wires that have come off their pins.

 

I have several of these units and they have proved amazingly reliable. However they have lots of integrated circuits in push-in sockets. If the unit has had a knock the ICs might need reseating.

 

Let us know how you get on.

 

Good luck, Alan.

[willjam39]

Thanks Alan

The dip switch is set for 10v and the switch on Negative

I shall have a look inside when I can get at it in the week. It has been a great unit and would be a shame if it is done.

Will

[ninjadingle]

That sounds like the connections inside your DB25 have come adrift. If you want a quick fix this cable worked for me at my old venue...

 

10 out of 10 DB25 cable

 

 

Not that cheap but should get you working.

[willjam39]

Hi Guys,

 

an update on the problem. I borrowed a second Showtec demux and it did the same as the first so it appeared to be a pin out issue.

 

the in house system has two desks, a very odd manual and a "digital" one that works with a little box plugged in to the D plug.

 

Aha! I thought they have a demux which works, but it turns out their system is running a different protocol to DMX. Luckily it turns out the trusty 520 has a port for that protocol aswell :S

 

It was a fun experience and at least the showtec is still going strong

 

Thanks for all your help guys