M Joel W Posted March 28, 2008 Share Posted March 28, 2008 Hi, I just received in the mail a 1.2kw HMI par made by LTM. I cannot find polarity markings on either the bulb or the socket and the bulb appears to fit into the socket irrespective of orientation. Will the bulb work no matter what or is there a way to know for sure that the bulb's orientation in the lamp head is correct before I strike it for the first time. Can I damage either the light itself or the bulb if I strike it with the bulb inserted with the wrong polarity? Thanks as always for the help, -Matt Link to comment Share on other sites More sharing options...
robert duke Posted March 28, 2008 Share Posted March 28, 2008 either way the electrons will flow. AC- alternating Current Link to comment Share on other sites More sharing options...
M Joel W Posted March 29, 2008 Author Share Posted March 29, 2008 Okay, now it won't turn on... The red light on the ballast turns on, as does the one on the lamphead. When I strike it....the ballast pops, but the light itself does nothing. And the ballast hums a bit after this but too quietly. The green light on the lamphead does NOT turn on. Thanks. Link to comment Share on other sites More sharing options...
Matthew Wilson Posted March 29, 2008 Share Posted March 29, 2008 Okay, now it won't turn on... The red light on the ballast turns on, as does the one on the lamphead. When I strike it....the ballast pops, but the light itself does nothing. And the ballast hums a bit after this but too quietly. The green light on the lamphead does NOT turn on. Thanks. Hey, Are you sure you have the correct Bulb? Par64 sounds like a tungsten bubble but everything is called different names in different places so can't be sure. Anyway.....if it is the right bulb then.... Check that the bubble is all the way in and locked in place. check the cables from the igniters are connected to the bulb holder. Plug it all in and check the connections. Check the lamp is on at the head. Try it. If it doesnt work then just about the only other thing it can be that you can check is the microswitch. When the lens door is closed it engages a push in switch that acts as a safety loop. If the switch is not engaged by the door being closed the lamp will not fire. Unplug the lamp, Open the door and locate the switch, check to see if it is being engaged by the door shutting, if not you may be able to adjust it so it does. If it still doesnt work then speak to your suppliers, because its probably not something you can do anything about. Hope it does work. Link to comment Share on other sites More sharing options...
M Joel W Posted March 29, 2008 Author Share Posted March 29, 2008 It's an old bulb: definitely par64. Same size as the tungsten lights, but a 1200w hmi. You can find these on ebay for about $350 per bulb. The HMI "bubble" itself is contained in a small bulb within the larger par64 enclosure. I can't find this alleged "microswitch" that you mention and I've read about in my lighting technician's handbook. I don't have the manual so I don't know where it is. I'm wondering if there isn't one because the par64 enclosure kind of acts as a protective lens? But the lamphead is behaving as though there is one and it's not switched on. The ballast pops but the light doesn't make a start up sound or anything. Anyhow, I'll look around... Thanks again, -Matt Link to comment Share on other sites More sharing options...
robert duke Posted March 30, 2008 Share Posted March 30, 2008 the ballast pop is the magnetic switch fliiping. the Hum sounds like it could be an igniter. Check all the connections and try it again. If this is a new purchase off ebay verify with the seller that it was working. you might also try to rent a ballast and try a different ballast. try cleaning the connections with an eraser. If it still doesnt work contact LTM Link to comment Share on other sites More sharing options...
M Joel W Posted March 30, 2008 Author Share Posted March 30, 2008 the ballast pop is the magnetic switch fliiping. the Hum sounds like it could be an igniter. Check all the connections and try it again. If this is a new purchase off ebay verify with the seller that it was working. you might also try to rent a ballast and try a different ballast. try cleaning the connections with an eraser. If it still doesnt work contact LTM Unfortunately it has socapex connectors and is LTM; my local rental place has veam connectors/arri ballasts. Also, I'm a college student without much money. Can't expensive repairs or rentals. Hence buying a used unit. I cleaned the contacts, checked the connections, etc. and it still has the same problem. There's a small black button on the ballast. Does this do anything? I haven't tried it yet. What is the ignition sequence exactly for these things? Maybe it's different from the arris I've used... Link to comment Share on other sites More sharing options...
JD Hartman Posted March 31, 2008 Share Posted March 31, 2008 Did the seller state that the unit was working and the used globe was good? It could be that the HMI globe has reached the end of its life (internal electrodes too far apart to strike). You might be able to get your local rental house to access the condition of the globe. Link to comment Share on other sites More sharing options...
timHealy Posted March 31, 2008 Share Posted March 31, 2008 (edited) When using HMI's, there are methods for testing components. But they often involve having another lamp just like it to swap parts and figure out which is bad. But since you don't, the first thing you can check is the voltage of your electric supply. Often the easiest thing to change is the header cable. In your case plug the light into the ballast directly without header. If it works now then it is a header problem. If it doesn't then you need to do more trouble shooting. It has been a while since I have used the LTM type HMI with the par 64 like bulb, but I do not recall them having a micro switch like HMI's that have a swing away door. I think the glass housing that the bulb was in is the UV protection. It would be next to impossible to use this light with a broken bulb. But I have been wrong before. Best Tim PS I would personally stay away from buying complex electronic optical devices such as HMI's on ebay. You never have any idea how badly they have been beaten up on other peoples jobs or left in the rain or dropped from a shelf etc etc.... Edited March 31, 2008 by timHealy Link to comment Share on other sites More sharing options...
M Joel W Posted April 1, 2008 Author Share Posted April 1, 2008 Thanks for the advice; tried it all and nothing. Thankfully the guy at the grip shop from which I bought the light on eBay has been very helpful and we're working something out. Seems like either the bulb or something in the head is broken. Or could be the ballast... But it's clear something's wrong and it's being worked out, thankfully. But thanks for the advice; it's all been helpful. Seems like I'll have to take it from here, though. -Matt When using HMI's, there are methods for testing components. But they often involve having another lamp just like it to swap parts and figure out which is bad. But since you don't, the first thing you can check is the voltage of your electric supply. Often the easiest thing to change is the header cable. In your case plug the light into the ballast directly without header. If it works now then it is a header problem. If it doesn't then you need to do more trouble shooting. It has been a while since I have used the LTM type HMI with the par 64 like bulb, but I do not recall them having a micro switch like HMI's that have a swing away door. I think the glass housing that the bulb was in is the UV protection. It would be next to impossible to use this light with a broken bulb. But I have been wrong before. Best Tim PS I would personally stay away from buying complex electronic optical devices such as HMI's on ebay. You never have any idea how badly they have been beaten up on other peoples jobs or left in the rain or dropped from a shelf etc etc.... Link to comment Share on other sites More sharing options...
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