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Hey guys, I'm afraid I need some assistance with by BIII. I finally finished all the modules of my 2nd Buffalo build (great fun, by the way!): Placids, Legato and BIII. I adjusted the voltages and current, hooked up the Legato and zeroed the offset, rechecked shunt current etc. Everything OK so far. Then I stacked the BIII on top and things went weird. One channel remained close to zero offset but the other channel not at all. So I disconnected the BIII from the Legato and checked the BIII outputs: right channel 1.75V/0/1.75V but the left channel only 0.12V/0/1.75V. The AVCC voltages are 3.5V, DVCC 3.3V, and the Tridents 3.3V, 3.3V and 1.2V. All LEDs light up correctly including the mute led. Do you have any suggestions? Or is this Buffalo toast? :( (one side note: in an attempt to solve the 4spdif (v1.0) lock problem I briefly lowered the BIII supply voltage to 5.0V, not realising this may be harmful to the Buffalo.. perhaps I shouldn't have done this?) Many thanks for your help! Mathijs The Netherlands File Attachment(s):  buffalo.jpg (288kb) downloaded 17 time(s).You cannot view/download attachments. Try to login or register.
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Originally Posted by: Stunts 
So I disconnected the BIII from the Legato and checked the BIII outputs:
right channel 1.75V/0/1.75V but the left channel only 0.12V/0/1.75V.
Where did you measure the output ? At the output header ? If so so it could be just a bad solder joint at the header / bad header ? If you did measure at the PCB, forget the above.
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Originally Posted by: avr300
Where did you measure the output ? At the output header ?
If so so it could be just a bad solder joint at the header / bad header ?
If you did measure at the PCB, forget the above.
Thanks for the suggestion, but it doesn't really matter where I measure... the + pads of channel 01, 03, 05 and 07 are all at the same 0.12V.
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I don't know if this is helpful: when the BIII is connected (after trimming the offset of Legato to 0V), the output of the Legato becomes
L +9.45V / 0 / -9.56V
R +9.60V / 0 / -9.59V
Please let me know if there's other information/measurements that may be of any help to determine if my Buffalo has passed away..... thanks.
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What I don't get is how all 4 dacs (half the 9018) dies. No, there's something else wrong.
I don't have a BIII so I'm not familiar with the switches. Have you consulted Leon's manual ?
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Originally Posted by: avr300 What I don't get is how all 4 dacs (half the 9018) dies.
Maybe they didn't, but the outputs are connected by three 0R SMD jumpers (J8, J9, J12) so I think there's no way to tell without removing those...  I guess it could be helpful to remove them and measure each of the output channels individually? (it was kind of painstaking to solder them nicely :) File Attachment(s): buffalo underside.jpg (327kb) downloaded 8 time(s).You cannot view/download attachments. Try to login or register.
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Update: I desoldered the three SMD jumpers J8, J9, J12 and measured the channels individually:
channel + -
01 126 mV 1747 mV
03 1749 mV 1747 mV
05 42 mV 1747 mV
07 1746 mV 1747 mV
So it appears that channel 01 and 05 are dead...?
Russ, Brian, what do you think? Is there anything else I can try? Thanks.
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That is how it appears, or somehow they got shorted?
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I did some more measurements:
01(+) to GND: 63
03(+) to GND: 1428K
05(+) to GND: 21
07(+) to GND: 1424K
01(+) to 03(+): 1320K
01(+) to 05(+): 84
01(+) to 07(+): 1410K
03(+) to 05(+): 795K
03(+) to 07(+): >2000K
05(+) to 07(+): 1410K
Indeed the suspects 01 and 05 don't look right. But I don't understand the ~1.4M of the other channels either.
01-03-05-07 (-) to GND: 928K
02-04-06-08 (+) to GND: 929K
02-04-06-08 (-) to GND: 930K
If 930K is normal for four channels combined, then one individual channel should measure approx. 3720K (correct me if I'm wrong)... Which would mean that the entire (+) side of the left channel is broken somehow…?
I don't know what to do with this beast :'(
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Russ, Brian, considering all of the above, what would be my options? I'm kind of hoping that you guys can help me out...  Thanks! Mathijs
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Solved!
Many thanks to Brian for the excellent customer service!
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