Poormusician Posted July 21, 2011 Share Posted July 21, 2011 Hi guys (and girls)! After being roped in by a local school to repair the zero 88 Alcora desk, I have now found that one channel on one of the two act 6 dimmers is crackling badly at everything lower than 100% and hence I'm looking for some advice on this. I'm no spring chicken when it comes to stripping down stage gear, and am a qualified sparky by the way. However, as these are hard wired in, and a bit of a faf to remove, does anyone have experience of said problem. I'm guessing it's probably a faulty triac? and if so, are these still available, or is there a compatible replacement part.Also, if anyone happens to know of any unwanted dimmers, I'd love to hear from you, as unfortunately with all the cut backs, the school has literally no money to spend on new gear. Anyway, enough of my rambling, and I'd be most grateful if any of you could help me with this matter. Many thanks, Ian Link to comment Share on other sites More sharing options...
pritch Posted July 21, 2011 Share Posted July 21, 2011 Crackling? You mean it actually makes a crackling sound, or are you trying to describe something the lantern on the circuit is doing? Personally, I'd be a little surprised if a triac crackled, I'd be more inclined to check for loose connections first. That said, it's not unheard of for dimmers to buzz quite audibly at certain intensities - they're normally silent at 0 and 100%, with different amounts of buzz in between. This may also manifest itself in the lanterns, too. Edit: Oh, could a passing mod shift this into lighting? Might get a few more reads that way. Moderation: Done Link to comment Share on other sites More sharing options...
mutley Posted July 21, 2011 Share Posted July 21, 2011 If it's a crackling noise from the dimmer, check for any erupted polyester capacitors. They normally have clear epoxy cases which have split, and spewed half of their innards out! This is a common problem on some of the old Strand dimmers. Replace all of them with suitable X or Y rated capacitors, not just the frazzled ones. Link to comment Share on other sites More sharing options...
Poormusician Posted July 22, 2011 Author Share Posted July 22, 2011 Many thanks Pritch and Mutley, and Mutley, the caps sound like a plan. (Having never opened a dimmer rack before, I wasn't exactly sure of what to look for). Also thanks for moving the post, I posted this inns bit of a hurry on the iPhone last night after a show, and obviously lost the plot! Cheers guys, really appreciated. Ian Link to comment Share on other sites More sharing options...
Andrew C Posted July 22, 2011 Share Posted July 22, 2011 Even older Strand dimmers (Mini 2) suffered from their output sockets loosing their springy-ness. Not gripping the plugs they arced and burned out. Link to comment Share on other sites More sharing options...
gingervit Posted November 4, 2011 Share Posted November 4, 2011 Check for dry joints on the pcb, you'll see them blackened if they are carrying current.. the crimps on these burnt out all the time. Link to comment Share on other sites More sharing options...
oilyspark Posted November 4, 2011 Share Posted November 4, 2011 Also on an Act 6; disintegrating fuseholders and poor connections to the choke tails. Qutie a few of the common Act 6 faults can lead to arcing. Lucien Link to comment Share on other sites More sharing options...
bigclive Posted November 5, 2011 Share Posted November 5, 2011 From my experiences the fuseholders on ACT 6 dimmers were a constant pain, particularly on well abused hire stock. They do indeed tend to go a bit crunchy after a while. Right now I'm rather peeved at being dumped with a stack of less than desirable old Act 6 fused dimmers in place of the more modern dimmers I requested. Link to comment Share on other sites More sharing options...
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