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I'm looking at a Crown DC300A that has a problem w. channel 2. With no load it puts out a nice sine wave on the scope. With an 8 ohm dummy load the top half of the waveform is clipped. Would anyone(Enzo?) have a schematic of this amp? It has the IOC circuit. Thanks in advance for everyone who helps out here!
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Yes I do, but really, call Crown. They can send you a nice copy. I'd have to scan several large fold-out pages in multi-scans.
If the output is clean but collapses under load, I first suspect a bad driver or open output device, or open ballast resistor.Education is what you're left with after you have forgotten what you have learned. -
Looking on Crown's website I found the operation manual for the amp. There was no schematic, but there was a layout of the driver board and the input board. There were also part lists, so that helped out some. I pulled the output xstrs and tested them with a Sencore Supercricket. They all test good ,but half of them are considerably lower in gain. I put 2 back in the circuit(similar gain) and fired it up. No IOC light and a full sine wave. With the age of all the transistors I'd probably change them all out if it were my amp,but it's not. ?Comment
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I am surprised the schemo is not in the operating manual. All the manuals I got with my old Crown stuff included them.
But the advice was to call Crown and ask for the drawings. Not look online. Usually they are quite helpful.Education is what you're left with after you have forgotten what you have learned.Comment
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Well,I ended up replacing the output xstrs on the one side and the amp is working great.Comment
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