Class I amp or I guess so

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#1 cqtsdss

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Posted 13 September 2011 - 11:44 AM

I'm not sure if I'm breaking the forum rules and I hope I am not. I have four units of JBL PRX518S over my workbench for servicing and I know is a CROWN design so I dare to post here in case anybody can give me some ideas or advice.

The thing is that I have found some of the final switching Qfets broken, I have removed them, and to check if there's nothing else broken, I turned it on before installing the new devices, but the power supply is generating a lot of noise as if there was already something wrong. I am getting into these new technologies but experience is at its weak, so I don't know if there could be a problem, which I can't find, by connecting the module (unloaded, of course) without the Fets.

On the first repair, I mean the first module I tried to fix, after I replaced the defective Qfet I turned it on and a few seconds after the power supply literally explode, so I am very worried about going ahead or not. I know that other technicians are simply (it is not the word I'd like to use) replacing the whole thing, but I refuse to throw this away, there is a lot of technology and I believe it can be fixed.

Looking for your help.



#2 Kevin Heber

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Posted 14 September 2011 - 02:22 PM

Sounds like a job for JBL Pro - http://www.jblproservice.com/forms/form_dir.html

This is a class D amp similar to the XLS Drivecore series, but that's about all I can help with.  Not because I am restricted from doing so -- but because forums aren't very good for general repair issues.