DMX to Analogue

[DoctorStar]

Evening folks,

 

After a pleasant couple of hour rigging lights we ran into a small problem. Our control line runs thus

 

Jester >> Betapack3 >>Betapack3>>Demux>>Betapack1.

 

Today, the Demux to Betapack1 end seems to have stopped working....faders go up and down on Jester....lights stay off (also no buzzzz as the dimmer channel powers up)

 

The Demux is a Botex Me72 and is set to Channel 13, its led illuminates on connecting DMX cable from previous Betapack 3. All DMX cables check out (test: Jester to Betapack3)

 

The Beta1 dimmer is fine as we were testing fixtures as we hung them using a small analogue desk.

 

So, it appears either the Demux is not spitting out a voltage or the D25 to 8 pin din cable thing is not working.

 

So having wandered to the periphery of my knowledge......

 

1. How can I check if the Demux is generating a control voltage without attaching it to a dimmer?

 

2. How can I check the D25 to 8 pin is working as it should i.e. a voltage across one end appears at the other?

 

Thank you in advance for any help

 

Ian

[pritch]

Meter it? Stick a meter, on a DC range, across Pin 8 (the centre one) and one of pins 1-6. You should get somewhere between 0-10v, depending on what intensity the channel's at.

[J Pearce]

Grab a multimeter and measure the voltage between 0V and the channel outs with the channels at full, both at the demux out socket (pin out is printed on the back of the botex demux) and at the end of the cable.

This will tell you which is at fault.

[MarkB]

If your DMX channel 13 is at full, should be able to observe 10v between pin 1 (channel 1) and pin 8 (ground) on the din cable.

 

DIN pin diagram: http://business.virgin.net/tom.baldwin/pinout-8din.html

 

note diagram is from wiring side.

 

Hope this helps

Mark

 

edit: pin number corrected.

[bruce]

I guess the d25 to din will have several dins on it. Are you sure you're using the right one? Are you sure it's in the right d25 socket?

[DoctorStar]

Hi Folks,

 

Speedy replies, TY.

 

I'm sure I have the right DiN and socket......it is left in-situ between shows. It worked last time and now it doesn't :(

 

I will get a multimeter from the science techs tomorrow and continue trouble shooting.

 

Thank for your encouragement.

 

Ian

[timtheenchanteruk]

ah, a school, never assume the plug/socket is the combination you left in there last time!!

[bruce]

 

I'm sure I have the right DiN and socket......it is left in-situ between shows. It worked last time and now it doesn't :(

 

But you did say you had unplugged it and used a small analogue desk when rigging.

[DoctorStar]

Fair point Bruce (sorry!). Equally fair point Tim.

 

I will start afresh tomorrow with plenty of things to target.

 

Thanks again.

 

Ian

[ianknight]

Depending which version of the ME72 you have - it might be something simple like the LM324 that drives those output channels has failed - there are some versions where these are socketed and so can be swapped fairly easily.

 

As a quick 'get round' you could use another DIN plug which would offset the channels by 6 or 12 and then repatch the Jester faders to drive those channels as normal.