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Amp Internals 2 |
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gerry_morales 
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Joined: 01 February 2015 Location: philippines Status: Offline Points: 7 |
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 Posted: 01 February 2015 at 12:57pm |
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hi there jr, i am also repairing the same amp on my repair table, an old ca9....... just wanna ask if the power supply board is a multi layer ......... i am having hardtime checking the schematics with regards to the psu brd, could not follow the traces.......... any idea if its a multilayer brd....
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LjudLahger
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Joined: 31 July 2008 Location: Sweden Status: Offline Points: 838 |
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Posted: 01 February 2015 at 2:17pm |
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Crown XTI 1002, 2002, 4002
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JR.junior
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Joined: 14 December 2009 Location: Slovenija Status: Offline Points: 1789 |
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Posted: 01 February 2015 at 2:22pm |
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yes, it's multilayerd. |
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Support the scoop technology, larger mouth plays louder!
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JR.junior
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Joined: 14 December 2009 Location: Slovenija Status: Offline Points: 1789 |
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Posted: 01 February 2015 at 2:22pm |
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What's the problem with the CA9?
Edited by JR.junior - 01 February 2015 at 2:26pm |
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Support the scoop technology, larger mouth plays louder!
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kedwardsleisure
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Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4947 |
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Posted: 04 February 2015 at 11:57pm |
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Crest 9001 Nexsys from earlier post. Board is totalled, this is going to be a dear fix.
All output transistors on one half the bridge open, heatsink badly pitted  Commutating fets and diodes welded to the case, board a charred mess 
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Kevin
North Staffordshire |
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odc04r
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Joined: 12 July 2006 Location: Sarfampton Status: Offline Points: 5482 |
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Posted: 05 February 2015 at 9:27am |
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Looks like that even besides the MIG welding that took place the output PCBs were in a pretty fiilthy condition. There's a lesson there...
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M4trix
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Joined: 23 June 2009 Location: Croatia Status: Offline Points: 445 |
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Posted: 05 February 2015 at 3:23pm |
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Hm strange.... If the heatsinks are live, connected to either positive or negative supply voltage and isolated from the ground, why is the damage around that spot. Guys, put some light on this case.
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odc04r
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Posted: 05 February 2015 at 3:56pm |
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It was all explained in another thread, I believe the heatsink arced to the chassis or another grounded part of the amp helped via all the dust that had built up in it. |
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M4trix
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Posted: 05 February 2015 at 4:20pm |
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Yep, Kevin made a thread about it. http://forum.speakerplans.com/crest-9001-interesting-article_topic90378.html Well, I don't like this Crest's design with huge live heatsinks. QSC has a better solution with grounded collectors topology. Edited by M4trix - 05 February 2015 at 4:21pm |
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kedwardsleisure
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Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4947 |
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Posted: 05 February 2015 at 6:27pm |
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qsc usually do have a better solution..apart from the GX series
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Kevin
North Staffordshire |
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michel29
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Posted: 09 February 2015 at 9:53pm |
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the crest 9001
failed with extreme moisture and dust ? it's 2nd version , with coated bus-bar |
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kedwardsleisure
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Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4947 |
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Posted: 09 February 2015 at 11:20pm |
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Dont think it helped
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Kevin
North Staffordshire |
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gerry_morales wrote: