|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
66.32.40.9
In Reply to: RE: Crown CE2000 repair posted by Thermionic27609 on February 13, 2010 at 17:34:59
Before I posted, I hadn't discovered that Crown has the service manual for this amp posted as a pdf for download, so I guess that answers my question.
I guess I haven't fully recovered from my encounter with Musical Fidelity's customer abuse team....
David
Follow Ups:
It pains me to say but the CE series is JUNK! I have 6 of them in my shop i would gladly GIVE you to get out of my way! I love crown amps and the Macro-tech series of amps was awesome! But everything since then has been bad news service wise!
The ce series has one large circuit board with very large heatsinks attached to the tops and surface mount parts on the bottom....do you see the problem with this...the big heatsink causes the circuit board to flex with any sort of vibration. the surface mount parts pop off and break there solder connections like popping corn! then amp goes poof! One look at the zillion revisions of this amp in the schematics will tell you the story first hand.
If you are really going to try and fix this hunk...1- you really have to understand amplifiers. if your not an experienced tech, this is not the place for you to start! go find an old Peavey or BGW to get your feet wet. If you are an experienced tech, then start by downloading and studing the Macro-tech schematics and get a handle on the Grounded Bridge and how the front end works. it is not like a conventional amplifier and until you understand how it works...it will be quite confusing. even for an experienced tech, getting a grip on just WTF is going on is a challenge. One you have a firm grip on the G.B tech and how the LVA stage works, then you can apply that to the CE amps.
Start by looking for cracked SMD devices and cracked solder joints. there are some large resistors that are known to be problematic.
Oh yeah... BTW VERY VERY VERY IMPORTANT!****** the input module connects with a thin ribbon cable. DO NOT POWER UP THE AMP WITHOUT THAT MODULE CONNECTED!!!!*** you will instantly blow the LM3080 SMD IC's and they are a PITA to get to. they are behind the relays and you pretty much have to pull the relays off the board to replace those IC's. not a fun thing to do!
The output devices are probably fine if its not blowing fuses. it is almost always bad solder joints on the PCB...bad bad design.
I wish you the sincerest best of luck. but honestly. my .02 cents is to chuck that thing in the garbage can, use it as a wheel chock, maybe a boat anchor, a door stop, anything but an audio amp...YMMV
Zc
As a postscript, I did manage to fix the CE-2000, but, having worked on it, I'm sure everything you said is true.
This one needed the field mod described in the manual where you remove a few parts, scrape off the adhesive used to hold them to the board, and replace them with new parts. After that, it worked.
It seems to me to have a bit of a rolled-off high end. I was thinking that they might have been voiced for horn-loaded PA cabinets so that they wouldn't sound screechy.
I have two CL-1 amps and recently one of them has developed a problem, upon powering up, the left channel passes the diagnostic check, butb the right side has the green signal lamp lit and the clip light is also lit and wont pass the diagnostic. I have been told this is a shorted output transistor. Is there any specific way these must be checked with a meter? (as in do they need to be removed from thew board before checking?)
thanks,
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: