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Old 21st December 2010, 10:03 AM   #391
phrarod is offline phrarod  United States
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Just for grins. Here's the Audio Note Dac board schematic (kit board not production board)
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Last edited by phrarod; 21st December 2010 at 10:11 AM.
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Old 21st December 2010, 10:38 AM   #392
la1209 is offline la1209  Hong Kong
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Maybe some area or pinout of the 74HC04 shorted to GND. You can check the pin without the chip, and check it point to point to see is there any point being shorted to ground.
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Old 21st December 2010, 11:05 AM   #393
Jogi is offline Jogi  Germany
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Hi,

it seems that the chips are not the reason, because you changed them all with no result.
Are you sure that all of the chips receive the 5V?
You should measure the voltage at the capacitors close to the chips.

If it is wrong there, the fault must be BEFORE the actual dac chips, either the salas shunt or the tl431 circuit.
I had a similar bug, because I soldered some wrong resistors (belonging to the tl431 circuit), so the chips had the wrong voltage, although the salas shunt was working properly.
When the tl431 has not enough voltage, it distorts btw.
I blew one ad1865, fortunately I had another one.

good luck, it is worth the trouble soundwise...


cheers,

Juergen
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Old 21st December 2010, 04:35 PM   #394
phrarod is offline phrarod  United States
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I did a continuity check to ground on all the pins of 74H last night and there was no short there.

Just now I removed the 8414 then tested the 74H. Same result
Then I removed the 1865 - Same result
Then I swapped in and out the CS and 1865 and no result.

Does this chip have a closer relationship to the CS8414 or the AD1865?

I get fine voltage on the V-in of this chip just not on all the v-out
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Old 21st December 2010, 06:58 PM   #395
phrarod is offline phrarod  United States
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At the suggestion of a tech I pulled the 74H chip and tried it and I have the same distortion.
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Old 21st December 2010, 10:10 PM   #396
phrarod is offline phrarod  United States
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Some progress.

I built a small rig and put one of the 74H chips in it and fed the chip voltage. In the rig all the pins that should have voltage do. IE they all have the proper 5V.

If I power the chip only in the board I do not get those voltages. This proves the chips are ok.
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Old 21st December 2010, 11:31 PM   #397
phrarod is offline phrarod  United States
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I completely give up. I'm happy for others who were able to make this board work but I cannot.

I looked at every single trace and touched up every single solder joint. There is no change at all when the chips are in the board. None.

I suspect a problem with the PCB but I have no clue. Its no frustrating and defeating.
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Old 22nd December 2010, 12:35 AM   #398
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Quote:
Originally Posted by phrarod View Post
I completely give up. I'm happy for others who were able to make this board work but I cannot.

I looked at every single trace and touched up every single solder joint. There is no change at all when the chips are in the board. None.

I suspect a problem with the PCB but I have no clue. Its no frustrating and defeating.
I not Know, what i can help you now??
only say, please sent to me, i can fix it to you!

I no known where it is wrong in the PCB??
there are many member was successful with PCB!
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
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Old 22nd December 2010, 01:14 AM   #399
phrarod is offline phrarod  United States
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Maybe I got the bad one of the bunch. I'll hope someone in the U.S. can help but if they can't I'll just put the old board back in and maybe send it to you.
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Old 22nd December 2010, 10:27 AM   #400
lucylu is offline lucylu  England
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Hello Well i have sorted the heater volts out 6.3 and hv +300.

On the other board the rails are + 5v -5V that was the easy part .

All the 5v points around the chips are ok except pin 12 on 1865 it reads 2.5 v traced it back to pin 12 on 8414 it reads the same ?

i noticed that the led l19 did not come on .

am taking apart to check for bad joints .

cheers john
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