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breweryfr  
#1 Posted : Tuesday, June 24, 2014 5:34:31 PM(UTC)
breweryfr

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Hi Russ & Brian,

After using my combo composed of 2 buffalo's + 2 Legato's, one channel of the Buffalo DAC is failed.
No more sound.....

I checked Voltage 5,47VDC, I switched the DAC on the Legato and the VReg with no success.

Can I send It to you for a repair ?


Best Regards,
Alex.
avr300  
#2 Posted : Tuesday, June 24, 2014 6:37:49 PM(UTC)
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Lets start by getting a pictorial overview.

Can you post a few pictures, just to let us see the setup.

- Buffalo (I,) II or III ?
- Have you checked output voltage of all the Tridents ?
- If the Tridents are of version 1, your ~5.5v input voltage is just at absolute max. It better and safer to use 5.2v (remember that when we manage to get it running again)
breweryfr  
#3 Posted : Thursday, June 26, 2014 7:18:53 PM(UTC)
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Hi AVR300,

Please find attached some pictures of my installation.
I reduced the voltage to 5,25VDC.

I swapped the VReg board and the DAC's to ensure the source of the problem is a DAC board.

Best Regards.

Edited by user Thursday, June 26, 2014 7:21:53 PM(UTC)  | Reason: Not specified

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breweryfr  
#4 Posted : Thursday, June 26, 2014 7:28:11 PM(UTC)
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And here the picture when the board is power supplied...
My Setup composed of Buffalo II v1.0 + VReg 1.0

Edited by user Friday, June 27, 2014 2:07:43 PM(UTC)  | Reason: Not specified

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avr300  
#5 Posted : Friday, June 27, 2014 4:38:02 PM(UTC)
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Originally Posted by: breweryfr Go to Quoted Post
And here the picture when the board is power supplied...
My Setup composed of Buffalo II v1.0 + VReg 1.0


So Buffalo II without Trident. Not so much than can go wrong.

On the faulty channel you don't get LOCK (led)?

How is the input arranged ?
Are you using SPDIF?
Check the SPDIF signal entering the faulty DAC.
breweryfr  
#6 Posted : Saturday, June 28, 2014 9:31:02 AM(UTC)
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You notice the Lock in enabled here.
Previously the picture was done without a feeding signal.

The SPDIF is wired in parallel on both DAC's.

I use 2 DAC's in Stereo mode, this way I can check each channel.
I swapped the OPAMP and Vreg to check the DAC with no success.

As I said, only one channel is OUT.
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avr300  
#7 Posted : Saturday, June 28, 2014 1:56:47 PM(UTC)
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Try swapping the u-processors

Edited by user Saturday, June 28, 2014 1:58:29 PM(UTC)  | Reason: Not specified

breweryfr  
#8 Posted : Saturday, June 28, 2014 5:29:10 PM(UTC)
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Swapped DAC's boards with no success...

Edited by user Saturday, June 28, 2014 5:31:56 PM(UTC)  | Reason: Not specified

avr300  
#9 Posted : Sunday, June 29, 2014 6:12:04 AM(UTC)
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That was not what I had in mind.

"Try swapping the u-processors"

The little 8pin DIL.


edit: Rereading your posts. Is this what you called an OPAMP ?


One more thing worth checking. Since you have no Tridents installed you have 3 little ferrite beads on the back side of the DAC board labelled (if I remember correct) L6-L7-L8.

If for some reason I cant imagine why one of these has lost connection the DAC will end up silent. Worth checking I think.

Edited by user Sunday, June 29, 2014 7:07:27 AM(UTC)  | Reason: additional info

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breweryfr  
#10 Posted : Sunday, June 29, 2014 12:48:11 PM(UTC)
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Yes , It's what I call OPAMP I already swapped.

The DAC end up with noise in one channel without feeding a signal and after some minutes a mute status.
I'll check the inductance you suggested....

Edited by user Sunday, June 29, 2014 1:01:58 PM(UTC)  | Reason: Not specified

Brian Donegan  
#11 Posted : Sunday, June 29, 2014 2:01:22 PM(UTC)
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Check the following voltages on the Buffalo:

Both AVCC outputs (OUT pin to GND)

VDD (measure from VDD to GND on the Trident header)

DVCC (measure from DVCC to GND on the Trident header)

VDD_XO (measure from VDD_XO to GND on the Trident header)


breweryfr  
#12 Posted : Thursday, July 10, 2014 5:21:32 PM(UTC)
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Here are my measures:

On Trident Header to GND
VDD 5,27VDC
DVCC 3,28VDC
AVCC 3,52VDC

I cannot find the VDD_XO pin, don't know what you mean.

avr300  
#13 Posted : Thursday, July 10, 2014 6:52:05 PM(UTC)
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Originally Posted by: Brian Donegan Go to Quoted Post
Check the following voltages on the Buffalo:
Both AVCC outputs (OUT pin to GND)


Check attachment #1, this is the AVCC shunt. You have to measure 2 voltages (right & left channel)
Measure between RED and BLUE pins, remember 2 measurements.


Originally Posted by: Brian Donegan Go to Quoted Post
Check the following voltages on the Buffalo:
1. VDD (measure from VDD to GND on the Trident header)
2. DVCC (measure from DVCC to GND on the Trident header)
3. VDD_XO (measure from VDD_XO to GND on the Trident header)


Check attachment #2. This is a trident header.

All in all you have 3 of those headers on the DAC PCB. Find them.

Never mind the pin marked VD. Forget about that. Measure between the GND (BLUE) and the third pin (RED).
All in all you have to measure 3 voltages.

Edited by user Sunday, July 13, 2014 10:21:39 AM(UTC)  | Reason: Not specified

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avr300  
#14 Posted : Thursday, July 10, 2014 6:54:32 PM(UTC)
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Using your own picture
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