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Repair of CJ2000d


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#1 paul beale

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Posted 28 July 2006 - 03:15 PM

Hello All,
         I am repairing a crown amp with shorted output transistors in one
ch.  I have replaced one in the high side and one in the low side. I checked
characteristics with curve tracer to be sure of gain match. Also replacements
have same green mark on case and same part number. Is it required to replace all outputs or is this OK?  It is not blowing fuses anymore but still in protect mode. It has 100v on speaker output relay.    
         I am having extreme difficulty with documentation.
Crown supplies JBL Pro.  with crude Photocopy PDF files of engineering diagrams with holes and bad spots that can not be read , instead of service manuals.
  This is a  revision 5 amplifier  that was made just a few months ago. It is
installed in a JBL Mpro sub cabinet.  I see a fair number of older ones of these, but rarely with bad output transistors.
         At flat rate warranty repair I am losing my shirt....... I cannot locate a manual
and  the JBL supplied  Crown schematic  diagrams are NOT readable.  This amp is
quite different  from previous  revisions.
Paul Beale

#2 DGlass

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Posted 31 July 2006 - 07:54 AM

QUOTE(paul beale @ Jul 28 2006, 03:15 PM)
Hello All,
         I am repairing a crown amp with shorted output transistors in one
ch.  I have replaced one in the high side and one in the low side. I checked
characteristics with curve tracer to be sure of gain match. Also replacements
have same green mark on case and same part number. Is it required to replace all outputs or is this OK?  It is not blowing fuses anymore but still in protect mode. It has 100v on speaker output relay.   
         I am having extreme difficulty with documentation.
Crown supplies JBL Pro.  with crude Photocopy PDF files of engineering diagrams with holes and bad spots that can not be read , instead of service manuals.
  This is a  revision 5 amplifier  that was made just a few months ago. It is
installed in a JBL Mpro sub cabinet.  I see a fair number of older ones of these, but rarely with bad output transistors.
         At flat rate warranty repair I am losing my shirt....... I cannot locate a manual
and  the JBL supplied  Crown schematic  diagrams are NOT readable.  This amp is
quite different  from previous  revisions.
Paul Beale
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The CJ amplifiers are a built to order product manufactured by Crown on the design and specifications of JBL and are a "JBL" product. As an OEM manufacture of the product Crown is not responsible for manuals or service documentation. All questions and inquiries on this product need to go to JBL.