Ghost_Bass Posted February 18, 2014 Share Posted February 18, 2014 Hey, i was hoping somebody over here could give me some help. During our last rehearsall we lost sound from one of our speakers, a RCF ART312a (MK1 i believe). The speaker powers up but the limit LED stays on and no sound in either the woofer or the horn. When powering down i hear a pop from the speaker evne with the volume rolled off. We weren't pushing it at the moment, i think there were only a couple of voices and an accoustic guitar going into them. The other cab is working has it should. Another piece of information that can be related (or not), a few moments before the failure we had the mains power from the electric board shutting down (probably due to too much power being drawn from the heaters). Uppon powering up everything was working until that speaker muted. Does anybody know what could have coused this? could this be as simple as a blown fuse inside? Is there a way to fix it myself (i have a very limited knowledge of electronics but enough to be able to operate a soldering iron without getting burned... most of the times)? This is the speaker: Regards, Marco Quote Link to comment Share on other sites More sharing options...
BOD2 Posted February 19, 2014 Share Posted February 19, 2014 It sounds like there is a fault in the amplifier section of the unit. There[i] MIGHT[/i] be some fuses inside but these amps are not designed to be serviced by the user - especially if you have no real experience of electronics. My advice would be to take it to get repaired. If you really want to check for fuses then (with the unit unplugged !) remove all of the screws around the amplifier section and the whole amp should slip out backwards - there will be one or two connectors that connect the amp section to the speakers. If you need to disconnect these then make sure that you make a note of which way around the connectors go so as to make it easier to put it back together - take some photos if this will help. Once the amplifier section is removed, check around the board for fuses - there may be several. If any blown fuses are found then they must be replaced with fuses of the same rating. Quote Link to comment Share on other sites More sharing options...
deepbass5 Posted February 19, 2014 Share Posted February 19, 2014 There is a fuse in the IEC socket marked 6 in your photo. check this first a 2.5 amp. You may have been operating below the recomended voltage due to volt drop from running heaters on the same circuit also if there is a trip internally it may have operated due to a spike on the mains when it tripped out. Check with RCF but worth a look inside. Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted February 20, 2014 Author Share Posted February 20, 2014 Thanks for the tips guys If the fuse on the ICE socket had blown i wouldn't have any power on the amp but that's not the case because it powers on and the LED's light up. It seems more like something to do with the inside of the cab that's shorted or burned and causes the amp to go in to protection on startup. I haven't had the time to open it up and take a look inside. Once i do it and if i see any sign of short circuit or burned components i'll replace them. From what i've been reading in the web this is a fairly common issue with the ART series. Some people atibue it to som faulty transistors and some say that it can be a short on the XLR input. I was hoping i could find someone on BC with a similar experience that could point me out to a couple of possibilities. Cheers Quote Link to comment Share on other sites More sharing options...
deepbass5 Posted February 24, 2014 Share Posted February 24, 2014 Yep sorry you said it powered up smoothing Capacitor on the power supply board is a favourite. Most electronics are amazingly robust but if they use cheap capacitors a low voltage or spike the power supply usually will get it first. If you can get it in front of an electrician he could put a meter across the power supply to eleminate that. RCF may be able to tell you what the operating voltage is after the transformer and smoothing capacitors. the rectified DC voltage. At least you will know you do not have to delve into the amplifier cicuit board. I do have two ART 312-A here but they are fine after 6 years now. But worried that you think this is common. Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted March 12, 2014 Author Share Posted March 12, 2014 [quote name='deepbass5' timestamp='1393279317' post='2378289'] Yep sorry you said it powered up smoothing Capacitor on the power supply board is a favourite. Most electronics are amazingly robust but if they use cheap capacitors a low voltage or spike the power supply usually will get it first. If you can get it in front of an electrician he could put a meter across the power supply to eleminate that. RCF may be able to tell you what the operating voltage is after the transformer and smoothing capacitors. the rectified DC voltage. At least you will know you do not have to delve into the amplifier cicuit board. I do have two ART 312-A here but they are fine after 6 years now. But worried that you think this is common. [/quote] Yep, still trying to figure this out. I had it on my bench and did not see any burnt components so i gave it a good clean with contact spray and a brush and it started to work fine for some time after i reassembled it but it failed again after a few minutes. I'm starting to think that i may need to replace the filter card, where the Lim circuit is installed. Here's where i've seen that it's a common failure: http://music-electronics-forum.com/t28333/ Cheers Quote Link to comment Share on other sites More sharing options...
Pastor Richmond Nhyira Aik Posted June 25, 2020 Share Posted June 25, 2020 i have an RCF art 745-a and the board is gone off, please can i get a new board to replace the faulty one and also how mach it will cost. Quote Link to comment Share on other sites More sharing options...
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