Rhythm Addiction Posted May 19, 2010 Share Posted May 19, 2010 I was running my lighting rig at a bike rally last weekend and my laser packed up. It's an Actor Mate AL20-Magic Box II and although it shows the appropriate colour on the output it's not producing any beam. There are no obvious signs of anything untoward but someone suggested that it may be the laser diode that has failed turning it into basically a useless LED. Does anyone else have any knowledge of what it might be and if it's DIY repairable?I've tried looking at the laser forum mentioned elsewhere on the Blue Room but couldn't find anything that struck a chord.I'm guessing though that it's going to be uneconomic to repair so I'll have to start looking for another DMX controlled multi colour one Link to comment Share on other sites More sharing options...
greenalien Posted May 19, 2010 Share Posted May 19, 2010 It'll probably be uneconomic for someone else to repair, but you have nothing to lose by pulling it apart yourself - you might be lucky and it could just be a loose wire or a fuse!However, cheap laser diodes can - and do - fail unpredictably. Luckily, there are lots of suitable replacements available on Ebay, just search around a bit. Link to comment Share on other sites More sharing options...
musht Posted May 19, 2010 Share Posted May 19, 2010 Being 3 colour might mean colour mixing dichro is loose or mucked up in some way, pop the lid and inspect, carefully.. Red and green laser modules are cheap, trying to line them up in one beam is, er, time consuming. Link to comment Share on other sites More sharing options...
law99 Posted May 19, 2010 Share Posted May 19, 2010 Check the alignment, open the top and with follow the beams... with a tiny about of smoke if needed. Some reflection mirrors might have got knocked out of alignment before it get to the scanning mirrors! Worth a try before chucking it out! Link to comment Share on other sites More sharing options...
KevinE Posted May 19, 2010 Share Posted May 19, 2010 I'm assuming this scans by stepper motor? If so, are the mirrors resetting at power up? Disco-grade lasers tend to have seperate power supplies for laser and scanning and usually these are extremely cheap and nasty switch-mode supplies which look like the guts out of a laptop adapter. Its common for just one or the other to go, meaning the laser is 'on' but is stuck shining either back into itself or away from the front aperture. If this is the case, take care when powering up with the lid off or you might get an eyeful, then it's welcome to the world of premature macular degeneration! Link to comment Share on other sites More sharing options...
Rhythm Addiction Posted May 20, 2010 Author Share Posted May 20, 2010 Being 3 colour might mean colour mixing dichro is loose or mucked up in some way, pop the lid and inspect, carefully.. Red and green laser modules are cheap, trying to line them up in one beam is, er, time consuming. Yep, it is time consuming. Been there and done that once before and that's a part of my life I'll never get back! :P A concurrent post has been automatically merged from this point on. I'm assuming this scans by stepper motor? If so, are the mirrors resetting at power up? Disco-grade lasers tend to have seperate power supplies for laser and scanning and usually these are extremely cheap and nasty switch-mode supplies which look like the guts out of a laptop adapter. Its common for just one or the other to go, meaning the laser is 'on' but is stuck shining either back into itself or away from the front aperture. If this is the case, take care when powering up with the lid off or you might get an eyeful, then it's welcome to the world of premature macular degeneration! Yes the stepper motors seem to go through a reset on power up but there seems to be no coherent beam at any point before the mirrors. There is a clear output of colour which changes depending on what commands I send it via DMX but the beam isn't there at all Link to comment Share on other sites More sharing options...
KevinE Posted May 20, 2010 Share Posted May 20, 2010 Check the DPSS module has the right voltages to it, usually 5V (its often marked on the pcb) before condemning the laser unit. Link to comment Share on other sites More sharing options...
Rhythm Addiction Posted June 2, 2010 Author Share Posted June 2, 2010 Just in case anyone else has a similar problem, here's what actually was wrong. A friend of mine who has experience of lasers from a scientific background took a look at it for me and it was the mirror alignment. Apparently a grub screw had come loose and as a result the mirror had actually reversed on the stepper so the beam was actually shining on the back of the mirror! Needless to say replacing the grub screw got the mirror back into position and it's all back working again. It looks like my caution with not 'looking' at the laser beam didn't allow me to spot what was actually the problem so although I feel a bit of a muppet at least I've not blinded myself and have had an expert deal with it. Link to comment Share on other sites More sharing options...
greenalien Posted June 3, 2010 Share Posted June 3, 2010 at least I've not blinded myself Not blinding yourself - or anyone else - is the major consideration with lasers - even small ones. Thanks for letting us know what caused the problem. Link to comment Share on other sites More sharing options...
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