Louis sullivan NLS Posted August 1, 2011 Share Posted August 1, 2011 Hello everyone, I looked around using google but could not find any information about this fault. My Martin MAC250+ gobo wheel doesnt seem to repond properly. When the fader/ wheel etc is at 0 posistion the gobo should go to open posistion, which it doesnt. The gobos don't always line up with the optics and not in the right posistion compared with the posistion of desk fader/ wheel. I checked that the grub screew on the stepper motor isnt loose which would be the obvious answer and the unit does not show any errors when booting up. Any help would be appreciated. Ta,Louis Link to comment Share on other sites More sharing options...
Smiffy Posted August 1, 2011 Share Posted August 1, 2011 Sounds like an issue with the sensor and the calibration of the wheel. Giving the gobo wheel sensors a clean with a bit of isopropyl alcohol on a cotton bud might be a good first stop. Cheers Smiffy Link to comment Share on other sites More sharing options...
mac.calder Posted August 1, 2011 Share Posted August 1, 2011 There is a hall sensor (magnetic sensor) on a PCB over the gobo wheel (the one Smiffy is talking about) - there is also a small magnet in a notch on the gobo wheel. Check the magnet is there - if not, there is problem 1. If the magnet is there, put an ohm meter across the two pins on the hall sensor (some fixtures have 3 pins connected - trial and error solves that). Spin the wheel - You will either get open circuit which changes to closed circuit when the magnet passes, or the other way around (cannot remember which on a 250). If it doesn't change, try adjusting the sensor so that it is closer to the wheel. Try again. Hopefully that will fix it. Link to comment Share on other sites More sharing options...
brainwave-generator Posted August 1, 2011 Share Posted August 1, 2011 Also, use your palettes and try going 'via' another gobo. If the indexing is completely gashed, it won't find anything properly. If it's only gashed on open, you may find you can go to one gobo then to open with no hassle. This happens to our Robes. Link to comment Share on other sites More sharing options...
timmeh2 Posted August 1, 2011 Share Posted August 1, 2011 Hi Also check that the motor stepping allows the wheel's magnet to align perfectly underneath the sensor. The hall switch has a very small active area and it's not uncommon on the early MACs for the wheel to slip meaning that the unit doesn't sense the switch changing between steps. Whilst it may be tempting to move the sensor as close to the magnet as possible, there is also a minimum distance it needs to be, else the field across the sensor will not change properly. All the bestTimmeh Link to comment Share on other sites More sharing options...
stuart.thompson Posted August 2, 2011 Share Posted August 2, 2011 When the unit is going through the reset procedure is the gobo wheel rotating smoothly ? Sometimes if the driver chip is damaged or a broken wire the motor can jerk around and may luckily find the magnet so the PCB will not show an error but the wheel will not reset into tthe correct position. Link to comment Share on other sites More sharing options...
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