danieleither Posted January 1, 2014 Share Posted January 1, 2014 I have a Martin Mac 250 (old type, just MAC 250) which works fine for a while but then loses it's DMX channel setting (strangely by one or two increments). I doubt it's relevant, but It's usually set to channel '54' and will work for a few weeks, then seems to stop working / responding but when I investigate the DMX channel has changed to 55 or 56. Simply setting back to the correct DMX channel and the fixture works perfectly again. I have noticed that the LED display occasionally flashes off for a fraction of a second or flashes '*' symbols - I believe when the head is moving fast. Has anyone come across this before and any suggestions as to the cause? Link to comment Share on other sites More sharing options...
gyro_gearloose Posted January 3, 2014 Share Posted January 3, 2014 It might be a dirty switch that's causing the DMX address to change. If you are comfortable doing it, just take the PCB out and solder some new switches on. Its not worth trying to clean them. As for the display showing **** every now and then, that's most likely down to a bad connection between the display PCB and the motherboard. The plugs and sockets either end of the cable might need a clean, or you may have a cable problem. Metering the cable won't help as them problem is intermittent. I'd start with checking the plugs first, and then try a new cable only if that didn't work. Link to comment Share on other sites More sharing options...
david.elsbury Posted January 3, 2014 Share Posted January 3, 2014 Dirty switch? maybe if they were dips , but they aren't. .. Link to comment Share on other sites More sharing options...
fliggygeek Posted January 4, 2014 Share Posted January 4, 2014 Check for dirt in the membrane buttons, but thats unlikely, more likely is the mainboard is starting to have corrupted memory, **** on the screen is a typical dead mainboard, but it sounds more like the eeprom is dying. Link to comment Share on other sites More sharing options...
gyro_gearloose Posted January 4, 2014 Share Posted January 4, 2014 Dirty switch? maybe if they were dips , but they aren't. .. I know that. I probably should have said 'worn out' rather than 'dirty'. But I do maintain that it is switch related rather than the memory. The likelihood of the eeprom failing in such a way that just the part that relates to the start address would be affected, and then affected so that it increases by 1 or 2 instead of being completely corrupted, is so low as to be extremely unlikely. The **** error message, according to the Mac 250 manual, means '... there is no communication between the control panel and motherboard', so I'd be inclined to check the cable. Link to comment Share on other sites More sharing options...
david.elsbury Posted January 4, 2014 Share Posted January 4, 2014 Still confused. From memory you have to have the display with the address showing on screen, then press enter, up/down to get it to where you want, then enter again to store the address. So for it to drift, you'd have to have multiple buttons faulty, acting in a very specific way?? Anyway, drifting OT here... Link to comment Share on other sites More sharing options...
danieleither Posted January 8, 2014 Author Share Posted January 8, 2014 So as a test, in theory, would the fixture work if I disconnect the button panel (ensuring the DMX and other settings are correct first) and run the unit for a few weeks and see what happens? Link to comment Share on other sites More sharing options...
gyro_gearloose Posted January 8, 2014 Share Posted January 8, 2014 So for it to drift, you'd have to have multiple buttons faulty, acting in a very specific way??Or it could be electrical interference on the cable between the display board and the motherboard. We already know there's a cable fault because of the **** error message that sometimes occurs while the fixture is operating. So as a test, in theory, would the fixture work if I disconnect the button panelYou won't know until you try it. I doubt it will cause any damage, just don't unplug it while the fixture is powered up. Edit: If it were mine I'd just check/replace the plugs at both ends of the cable between the two boards as the contacts may have aged. I'm repairing a set of 918s that have this exact problem with their sensor looms Link to comment Share on other sites More sharing options...
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