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I have my BIII signing for a few days, but I only listen to it briefly (<1 hr) as I am busy. Yesterday, I turn on my BIII like normal, I have more time listen to it, but after 3 hour I smell something burning, I immediately switch off the power. When I open up the cover, it appear the 9V toroidal trans is burning. It is so hot it melt the plastic of casing, smoke is coming out from it. Other component seems ok visually: LCDPS, BIII, tridents, 4-Channel S/PDIF (or AES-EBU) Input Module. I have a BII in my living room, I took the 9V toroidal trans over to test if everything is working. It does power on and sing but there is a high pitch sound from speaker after 2 second I turn on. I have tried everything I know to see which component giving me that trouble: -I change LCDPS with Placid HD -Change trident one by one -Remove 4-Channel S/PDIF (or AES-EBU) Input Module with no input -Change CD player -Change AVCC -Change firmware IC (IC8) -Change every setting All fail to eliminate the noise. Can you suggest me what else should I do? Note: I am using tube as output stage, but I do the same to my other setup in BII. Edited by user Saturday, December 3, 2011 6:53:55 PM(UTC)
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Rank: Advanced Member
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It seems like your transformer is destroyed. Have you measured the output? You should also measure/inspect for shorts on the input of the PSU it was originally connected to (LCDPS I guess?). A bit strange that it should happen after several hours, but its my best guess...
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Rank: Advanced Member
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I dare not to power up the destroyed trans to measure. When I received it, I saw the saw the plastic tape around the trans is very loose, I didn't bother about that, maybe I shouldn't use it at all, bad luck.
Back to the problem, I think I only left 2 thing to test, the clock and the 9018 chip. Anyone got any idea what the part is and how to change it?
Thanks.
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I would just check for a short at the psu input with the whole system together. The problem is almost certainly a bad trafo, a wiring issue at the trafo, or a problem with the input section of the LCDPS.
Check the rectifier orientations on the lcdps. If it was a bad trafo, I will certainly replace it, but that would be an uncommon failure.
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Rank: Advanced Member
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Brain,
I replaced the bad trans with a working trans from my BII system, there is no problem with the LCDPS. I tested both side of LCDPS, both also working fine. The problem now is the noise issue after power on for 2sec. I tested everything I know and swap with Old BII system I have. I couldn't eliminate the noise.
I can only think of changing the clock or 9018 chip. Is there other way? Or can I send it back to you?
Thanks.
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What are you using for an output stage? What you are describing does not sound like an issue with the clock at all. But rather is sounds more like instability of some sort like oscillation.
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Rank: Advanced Member
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Russ White wrote:What are you using for an output stage? What you are describing does not sound like an issue with the clock at all. But rather is sounds more like instability of some sort like oscillation. I use tube output stage, it is the same I use in my BII that I have been using for some time. Is there anyone mate BIII to tube output stage before? If it is not recommended, I don't mind to get an IVY. Actually I didn't know what is the problem but I tried change most of the thing I know and only left the clock and 9018 chip haven't change. Thanks.
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Rank: Advanced Member
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Problem solve by changing tube output stage with IVY III. It is the tube output that is the culprit.
The same tube output stage works in BII but not BIII. Is a mystery for me, I wish I have a scope.
Thanks Russ and Brian for the help.
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