andyfranci Posted February 27, 2004 Share Posted February 27, 2004 Hi, I just want to know what could be the problem with P2000 Electro-voice power amp that when powered up it goes on protect instead of starting normally. I am sound engineer and also have knowledge in maintainance of audio system such as power amp mixers apeakers etc. I have tried to chech if the power transistors of the amp is already damaged but they are not. what suprises me most is that some times when open the system and chech through the board and I couple it back and power it up, it starts operation nomally. But the moment I try put speaker load on it and it function for a while it goes back on protect. I presently have about twenty or more of this particular model in my audio system and about three of them are already giving this problem. I want to know if anybody has come accross this challenge before and what could be the possible solution. Thanks for any assistance Andrew Link to comment Share on other sites More sharing options...
James Posted February 27, 2004 Share Posted February 27, 2004 Is the bias current through the power transistors to high causing them to overheat and resulting in a thermal shutdown? James Link to comment Share on other sites More sharing options...
andyfranci Posted February 27, 2004 Author Share Posted February 27, 2004 Thanks very much The issue is that when I turn the amp on it stays on protect even without any load on it. Normally when you turn the amp on the two sides' protect light should come on, the fans speed for some seconds and stop, then simultaneously the protect lights go off. But now the reverse is the case. Andrew Link to comment Share on other sites More sharing options...
James Posted February 27, 2004 Share Posted February 27, 2004 Is the protect relay driven? If so is the relay getting the signal to switch and not or is there something stopping the signal from getting there? Ok, Just looked at the scematic for the amp and it looks like the protection is triggered by PSU presence and PSU temperature, If protect doesn't come on without load then I suppose it's safe to assume that this side of things is OK The other trigger is "Current Limit" protection which protects against temp DC and HF - This is probably the area you need to look into - either you have an over sensitive sensor or there is a genuine fault. I assume you have the schematic - If not Look here (page 4). Good Luck James (Who doesn't know anything about sound or electronics....) Link to comment Share on other sites More sharing options...
andyfranci Posted February 29, 2004 Author Share Posted February 29, 2004 Many thanks James I will have a check on the amps on monday and I will feed you back. Andrew Link to comment Share on other sites More sharing options...
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