judokabdg Posted October 17, 2016 Share Posted October 17, 2016 Hello Guys I have problem with my moving head (Futurelight MH840) - There is loud buzzing sound coming out of the base of the head. I already replace ignitor twice. Any Ideas ? I believe this maybe faulty ballast . If it is ballast would it be possible to use one from other 575 watt moving head ? Link to comment Share on other sites More sharing options...
judokabdg Posted October 20, 2016 Author Share Posted October 20, 2016 Hello Guys I have problem with my moving head (Futurelight MH840) - There is loud buzzing sound coming out of the base of the head. I already replace ignitor twice. Any Ideas ? I believe this maybe faulty ballast . If it is ballast would it be possible to use one from other 575 watt moving head ? pls help:) Link to comment Share on other sites More sharing options...
timsabre Posted October 21, 2016 Share Posted October 21, 2016 Hello Guys I have problem with my moving head (Futurelight MH840) - There is loud buzzing sound coming out of the base of the head. I already replace ignitor twice. Any Ideas ? I believe this maybe faulty ballast . If it is ballast would it be possible to use one from other 575 watt moving head ? pls help:) Does the lamp work? There are a number of things could cause buzzing. Not all ballasts are the same even for the same lamp power, so swapping them is not a good idea unless you are sure it is compatible with the lamp. Link to comment Share on other sites More sharing options...
Jivemaster Posted October 21, 2016 Share Posted October 21, 2016 You are working in an area with high voltages (25KV typical for the igniter) and high currents. ONLY the correct parts should be used. "Buzzing" can come from most components, through being broken or just simply slightly loose. Do you have a manufacturer approved repairer in your area to look carefully and skillfully inside the covers? Do you have a source of proper manufacturer's spare parts? NO I would not mess with "similar" parts or spare parts sourced from the internet. Link to comment Share on other sites More sharing options...
judokabdg Posted October 22, 2016 Author Share Posted October 22, 2016 k Link to comment Share on other sites More sharing options...
judokabdg Posted October 22, 2016 Author Share Posted October 22, 2016 This sound appears once I switch lamp on. I already replaced ignitor four months ago as lamp did not want to start at all. After replacement of the ignitor lamp was starting ok , however buzzing sound was coming out of the base as soon I turned lamp on. Now lamp is not starting at all . I think that ignitor is broke again. I just wonder if ballast causing the issue. Just to clarify this is Futurelight MH840 - so it is old unit, I am not sure where can I source the ballast from and it is way too expensive for me to get professional to fix it. I worked in production company for few years and I serviced number of Martin and Robe lights - I just don't have any experience dealing with ballast, I was hoping that some of you guys will point me to right direction. Hello Guys I have problem with my moving head (Futurelight MH840) - There is loud buzzing sound coming out of the base of the head. I already replace ignitor twice. Any Ideas ? I believe this maybe faulty ballast . If it is ballast would it be possible to use one from other 575 watt moving head ? pls help:) Does the lamp work? There are a number of things could cause buzzing. Not all ballasts are the same even for the same lamp power, so swapping them is not a good idea unless you are sure it is compatible with the lamp. Is there any way of checking if ballast is compatible or not? Link to comment Share on other sites More sharing options...
timsabre Posted October 22, 2016 Share Posted October 22, 2016 Just to be clear it buzzes when you turn on the lamp, rather than when you apply power to the fixture? (I'm not sure if the lamp is switched on these) I would contact Robe about a suitable replacement ballast, I think they manufactured these units. Do you have more than one unit so you could swap parts between units for testing? Link to comment Share on other sites More sharing options...
Brian Posted October 22, 2016 Share Posted October 22, 2016 The ballast for an MH840 is type 'AL575FV' and is also used in a number of Robe products. It's available as a spare part and looks to cost around £120. Link to comment Share on other sites More sharing options...
judokabdg Posted October 22, 2016 Author Share Posted October 22, 2016 The ballast for an MH840 is type 'AL575FV' and is also used in a number of Robe products. It's available as a spare part and looks to cost around £120. Thank you Link to comment Share on other sites More sharing options...
Jivemaster Posted October 22, 2016 Share Posted October 22, 2016 If at any time an accumulation of smoke, fog or haze on the wires or body of the lamp holder there is the possibility that fog oil with attached dust will be causing tracking across the surface of the holder. IF you go to spending money on parts add a lampholder to your list. Look at the pins on a burned lamp, if the pins show burns in the contact area then the lampholder has weakened with heat and needs replacing. Link to comment Share on other sites More sharing options...
pscandrett Posted October 23, 2016 Share Posted October 23, 2016 If it's an old unit then it's almost got ferromagnetic ballasts and transformers. They work by manipulating currents through magnetic fields (caused by the current) and back again, with lots of thin wire wound around essentially a large lump of iron. These wires are stuck down in their coils around the iron on manufacture but it's possible that some windings have come unstuck and are vibrating in the magnetic fields, causing a buzzing. It might not be your problem, but if it sounds like it's coming from the base near the ballast and transformer, it's something to check (and can be solved fairly straightforwardly if it's an external wire by sticking it down again). Edit: Since it only buzzes when the lamp is on, my bet is a loose wire on the ballast. Link to comment Share on other sites More sharing options...
judokabdg Posted October 24, 2016 Author Share Posted October 24, 2016 thank you guys I will check both lamp holder and loose wires . I will let you know :) Link to comment Share on other sites More sharing options...
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