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BII- Legato no sound balanced + - DC keep changing on power cycle.
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Happy New Year, guys! I have been happily using my BII along with legato for a year or so till recently one day it stop to make any sound while the music is fed. I try to repeat the suggested initial adjustment routine in guide for legato, set the CCS current at ~350ma for placid BP and set the legato SE dc level and balanced + - DC level to zero as stated in the manual. The DC level stay put upon power cycle with legato only, but as soon as reattach BII to legato, i get 10-100mV dc over balanced + and - and the level keep changing as I turn off and on the dac. No music. Could any one let me know what is wrong and how I can diagnose the problem? Thanks! -John Edited by user Tuesday, January 1, 2013 5:45:28 PM(UTC)
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Is the mute LED lit? Pictures could help.
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Hi Russ! Wish you a happy and successful 2013. The mute and lock led on upon I2S feed. Currently a brand new LDBPS is powering legato, in order to eliminate placid BP as source of the problem. When I2S source is disconnected both mute and lock used to be off when I started to diagnose, but strangely now both LED are on even with no I2S feed. The DC level between + and - of the balanced output of legato changes between 10-140mv upon power cycle. Picture posted. Edited by user Tuesday, January 1, 2013 7:44:41 PM(UTC)
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Rank: Member
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I have isolated B II from legato and I2S input and the DC between bII output + and - still have DC level varying 10-200mv upon power cycle. I can zero DC level on legato output no problem if it is disconnected from B II. I have tridents installed on B II and 2 of them show 3.3v-3.4V between out and ground but Ground to VDD is only 30mv. Would this be the problem?
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It is definitely a problem.
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I guess the VDD trident should be fixed before I can diagnose further. How would I go about i? Why would just one of these go suddenly bad? Edited by user Wednesday, January 2, 2013 8:49:30 PM(UTC)
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It's the 1.2v Trident, the one which has the hardest job to do. Has it ever been exposed to more than 5.5v at it's input ?
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Rank: Member
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Never. BII has been powered by placid which is set to be max 5.45 at their peak after start-up. After that it stays at 5.40V. Any idea how to diagnose and fix the VDD trident?
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Rank: Administration
Groups: Administration, Customer
Joined: 10/24/2006(UTC)
Posts: 3,979
Location: Nashville, TN
Thanks: 25 times
Was thanked: 89 time(s) in 83 post(s)
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It's not usually cost effective to repair one. If you decide to replace it the newer version of Trident is much better anyway.
It is usually the opamp(common) or one of the bipolar transistors (also common) or the LED(very rare) that gets damaged.
This type of failure is usually caused by an inadvertent short, power surge, or ESD.
It also can sometimes be something as simple as a solder whisker or dry solder joint.
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BII- Legato no sound balanced + - DC keep changing on power cycle.
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