Jonni Posted March 1, 2019 Share Posted March 1, 2019 I've been asked to look at an old install in a school.They have 4 Tempus Dimmers with a Showtec Multi Exchanger.The issue that was reported was that the more channels they put on, the brightness of all the lanterns on starts to drop. Having had a proper look it seems that the Demux or its cabling might be the issue. The order of control of the dimmers seems somewhat messed up. The D sub from the demux goes to 4 bleecon sockets. They appear to be wired as follows:DEMUX Output 1D Sub 1-6 to Bleecon 1-6D Sub 25 to Bleecon 8 DEMUX Output 2D Sub 7-12 to Bleecon 1-6D Sub 25 to Bleecon 8 DEMUX Output 3D Sub 13-18 to Bleecon 1-6D Sub 25 to Bleecon 8 DEMUX Output 4D Sub 19-24 to Bleecon 1-6D Sub 25 to Bleecon 8 I hooked up a single dimmer to each of the four Demux outputs and this is what I got. The desk was patched 1-1. DEMUX Output 1Dimmer Channel 1 - DMX ??Dimmer Channel 2 - DMX 23Dimmer Channel 3 - DMX 21Dimmer Channel 4 - DMX 19Dimmer Channel 5 - DMX 17Dimmer Channel 6 - DMX 15DEMUX Output 2Dimmer Channel 1 - DMX 13Dimmer Channel 2 - DMX 11Dimmer Channel 3 - DMX 9Dimmer Channel 4 - DMX 7Dimmer Channel 5 - DMX 5Dimmer Channel 6 - DMX 3DEMUX Output 3Dimmer Channel 1 - DMX 1Dimmer Channel 2 - DMX 24Dimmer Channel 3 - DMX 22Dimmer Channel 4 - DMX 20Dimmer Channel 5 - DMX 18Dimmer Channel 6 - DMX 16DEMUX Output 4Dimmer Channel 1 - DMX 14Dimmer Channel 2 - DMX 12Dimmer Channel 3 - DMX 10Dimmer Channel 4 - DMX 8Dimmer Channel 5 - DMX 6Dimmer Channel 6 - DMX 4Does anyone have any ideas? Link to comment Share on other sites More sharing options...
Glyn Edwards Posted March 1, 2019 Share Posted March 1, 2019 It looks like a "simple" miswiring between the DSub and the Bleecons. There are various wiring conventions used for the DSub breakout and unless you have the right one you get all sorts of strangeness, which might explain what you're seeing.The circuit you can't identify will be the technical earth which the dimmers reference. If the voltage rises in this, (because it's being fed, rather than tied to earth) then the relative difference will be reduced and the dimmers output would fall accordingly. The simple answer is to source the correct adaptor. If you're confident with a soldering iron it may just be a rebuild, but I hate soldering bleecons and would rather spend the money and buy the lead. Also check if the Demux is set up for the correct polarity control output. Feeding dimmers expecting a 0 to -10v with a 0 to +10v signal will do all sorts of strange things... Link to comment Share on other sites More sharing options...
CPlater1 Posted March 1, 2019 Share Posted March 1, 2019 From the manual, it looks like the DSub pinout is DSub - Channel1 - Earth2 - 233 - 214 - 195 - 176 - 157 - 138 - 119 - 910 - 711 - 512 - 313 - 114 - 2415 - 2216 - 2017 - 1818 - 1619 - 1420 - 1221 - 1022 - 823 - 624 - 425 - 2 ThereforeBleecon 1 - pins 13, 25, 12, 24, 11, 23, 1Bleecon 2 - pins 10, 22, 9, 21, 8, 20, 1Bleecon 3 - pins 7, 19, 6, 18, 5, 17, 1Bleecon 4 - pins 4, 16, 3, 15, 2, 14, 1 Link to comment Share on other sites More sharing options...
ianknight Posted March 1, 2019 Share Posted March 1, 2019 From memory - with the multi-exchanger, the outputs "hop" back & forth across the D pins and don't run in a straight line (it caught me out the first cable set I made!). When Strand badged the unit as an S72, they shipped it with some D adaptors that crossed the wiring so you could use the bleecon to D connectors from Strand "black box" demuxes. The multi exchanger will happily run Tempus's - it's not too keen on Mini 2's though as the outputs are direct from the internal LM324's and the Mini 2 inputs sink a bit too much current - they'll work but the unit will need repairing after about 30 hours use or so. Link to comment Share on other sites More sharing options...
springgrove Posted March 1, 2019 Share Posted March 1, 2019 From the manual, it looks like the DSub pinout is DSub - Channel1 - Earth2 - 233 - 214 - 195 - 176 - 157 - 138 - 119 - 910 - 711 - 512 - 313 - 114 - 2415 - 2216 - 2017 - 1818 - 1619 - 1420 - 1221 - 1022 - 823 - 624 - 425 - 2 ThereforeBleecon 1 - pins 13, 25, 12, 24, 11, 23, 1Bleecon 2 - pins 10, 22, 9, 21, 8, 20, 1Bleecon 3 - pins 7, 19, 6, 18, 5, 17, 1Bleecon 4 - pins 4, 16, 3, 15, 2, 14, 1I have made a couple of breakout boxes MultiExchanger-D25 <-> 4x 8-pin DIN, and I agree that this is the pinout that I used. Nigel Link to comment Share on other sites More sharing options...
Jonni Posted March 4, 2019 Author Share Posted March 4, 2019 Thanks everyone. I'll look at remaking the cables today. Link to comment Share on other sites More sharing options...
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