simduv Posted December 18, 2007 Share Posted December 18, 2007 Hi there,Just wondering if anyone could help me with the following... Last night during a gig one of my Robe XT 160s lamps' stopped working, even though the fans are new I checked them and they are working fine. After the gig I ran the head in stand alone mode to recreate the problem and here is what happened.... The lamp sparked up on initial power up as per the norm stayed on for a few mins and then turned off, a fw seconds later it re-ignited stayed on for a matter of seconds then died once again, the third time it came back on it didnt spark properly and the bulb produced a faint white light glow. There didnt seem to be a pattern in the length of time the bulb was fully ignited to when it died. I also repeated the test with all covers removed from the head and the bulb removed from the reflector, in order to eliminate any over heating problems, the results were exactly the same. So any suggestions on what may be causing this will be warmly welcomed....I have my next gig on Friday and really need all of my heads working, so please help!! Thanks in advance. Simon. Link to comment Share on other sites More sharing options...
Tim Edwards Posted December 18, 2007 Share Posted December 18, 2007 Hi, Well for starters.... Don't ever run a moving head with the lamp outside of the reflector!!!! To be honest I don't know much about the Robe range so I'm not going to try to diagnose your problem. But for god sake don't do dumb things trying to fix kit! :** laughs out loud **: Tim Link to comment Share on other sites More sharing options...
simduv Posted December 18, 2007 Author Share Posted December 18, 2007 Hi, Well for starters.... Don't ever run a moving head with the lamp outside of the reflector!!!! To be honest I don't know much about the Robe range so I'm not going to try to diagnose your problem. But for god sake don't do dumb things trying to fix kit! :** laughs out loud **: Tim To be honest I dont see why running the head with the lamp outside the reflector is a major issue Tim, the bulb was secured and had plenty of clearance....but each to their own!! Link to comment Share on other sites More sharing options...
johnhuson Posted December 18, 2007 Share Posted December 18, 2007 The problem is that the lamps produce very high amounts of UV light which will damage your eyes if you run the unit with the covers off (there is a UV filter between the lamp and optical train to stop this during normal use). I speak from experience from my younger years, the pain is like having arc eye from welding, feels like you have grit in your eye. It does heal itself over time but the longer the exposure the worse it is. Link to comment Share on other sites More sharing options...
KevinE Posted December 18, 2007 Share Posted December 18, 2007 Good advice from John on the UV! By the time you feel any discomfort it's too late. Luckily the 150W lamp is not the largest in the world and it's well shielded in a metal reflector in the Robe but still, do take care. The lamp going on-off is quite common with worn discharge lamps and is known as cycling. It's telling you to change the lamp! The chemical process is quite complicated (google it to find out more) but this is exactly what happens when the lamp reaches its end of life. Of course poor ventilation can cause it to cycle on the overheat thermostat but you say you've already cleaned the vents out so no problem there (The robe's do get mucked-up quickly!!). The Robe uses the CDM150 S/A-T, these also get dimmer with age, luckily they're reasonably priced. Bear in mind that ageing discharge lamps can explode as they get tired....another good reason for not running it with the cover off. They can flirt pieces of their envelope several metres!!!!! Make sure a replacement lamp is the S/A-T version, this is the 'short arc' type. Putting the standard type in looks the same and will work and save you a few quid but the light output will be very disappointing indeed. http://www.atlaslightingsupply.com/CDM150T6.jpg The not-striking but just-glowing symptom is simply because the fixture has tried to re-ignite the lamp when it's too hot. The lamp has to cool right down (say 10 mins) before it will re-ignite, this is correct even in a new lamp and again is due to the way the lamp works chemically. Don't worry about it, just avoid trying to power up the Robe's when they've already been on a while, give them time to recover, or they wont work! It's called Cold Restrike, google that as well if you want, it's been covered on here many times!! Link to comment Share on other sites More sharing options...
simduv Posted December 20, 2007 Author Share Posted December 20, 2007 Thanks for all the advice guys, I had forgotten to mention that I did try a new lamp but was experiencing the same problems.... When I went back to work the next day, I noticed that in the test mode, the lamp was striking out at the same point pn the test cycle.....the culprit became obvious....a damaged supply wire to the bulb, which turned out to be the wire from the ballast. The wire had actually partially melted due to a cable tie havimg wworked itslef loose and not holding the wire in place correctly. Anyway ater a new wire, some new cable ties and lots of swearing ... its all fixed and ready for the rest of this mad month!! Thanks guys...sorry for the typos...long day!! Simnn. Link to comment Share on other sites More sharing options...
KevinE Posted December 21, 2007 Share Posted December 21, 2007 I had a similar fault but with a couple of Coemars...and it was the earth lead that had chafed through!! Worth checking on any moving head I suppose. Link to comment Share on other sites More sharing options...
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