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Alien DAC v1.1 Construction Thread - Page 98

post #1456 of 1560
9/29/08 at 6:38pm
Quote:
Originally Posted by Ub3rMario View Post
Yeah its just an old analog rat shack meter. Thanks for the link i think i'll order one!
I wouldn't order one and pay as much as (if not more than) the meter itself in shipping...there are several stores in Washington
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post #1457 of 1560
10/3/08 at 7:05pm
I just saw sparks fly from my pcm chip as I was testing for shorts.
Probably charge left from the caps.
Crap, that can't be good >_<

I'm panel mounting the usb receptacle, so I hook up the 5v line, and I get no indication of anything. I was just about to toss it, when the led flickers on!

I should've probably drained the caps again before I tested for shorts, cause my meter touched one of the pins, and spark!

Is there any remote possibility that the chip isn't fried yet?
Would hooking up D+ and D- do anything?
Also, I left pins 13/14 and 15/16 shorted when I tested the dac, with nothing connected to the output.
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post #1458 of 1560
10/3/08 at 7:21pm
Oh, and pictures...
top
bottom

Yes, I scratched off some of the green; I got reaaally aggressive with that chip after a while.

If the third from last pin looks bridged, it's because it is. (I accidentally bridged it after I tested it)

This was my first smd job.. no tweezers, no flux, fatty solder and tip... I think building this thing was the most frustrating thing I've done in my life, specially since I had to hold down the smd parts with my finger (although it kind of safe-guarded against overheating the parts, it also melted off my fingers!) >=o
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post #1459 of 1560
10/5/08 at 12:12pm
I just finished my first Alien with the kit from GlassJar. Everything seems to work: voltages check ok, the Alien is recognized by the OS, and sound comes out of the hp socket. I'm only puzzled by the extra resistor in the kit marked 5V, I did not find a place on the board for it, and there's no mention of it in the schematics. Any ideas?

It was my first shot at SMD soldering, and it took a while to get the hang of it, especially with my cheap iron, so the joints on the bottom are better made than the ones on top that I did first. My Dremel skills are not great, but I can always get a new tin case as they are so cheap.


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post #1460 of 1560
10/5/08 at 3:28pm
it's to use with external power, you don't need it.

Cool tin, I wish we could get em like that on this side of the pond
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post #1461 of 1560
10/5/08 at 4:14pm
Quote:
Originally Posted by JamesL View Post
I just saw sparks fly from my pcm chip as I was testing for shorts.
Probably charge left from the caps.
Crap, that can't be good >_<

I'm panel mounting the usb receptacle, so I hook up the 5v line, and I get no indication of anything. I was just about to toss it, when the led flickers on!

I should've probably drained the caps again before I tested for shorts, cause my meter touched one of the pins, and spark!

Is there any remote possibility that the chip isn't fried yet?
Would hooking up D+ and D- do anything?
Also, I left pins 13/14 and 15/16 shorted when I tested the dac, with nothing connected to the output.
The PCM will take some abuse, but hard to say. I rebuilt a users Alien (transferring all parts to a new board), and applied heat longer than recommended when removing the PCM from the old board. It still worked.

I didn't catch what you meant about D+ and D- until I reread that you are panel mounting the USB jack. If you have proper 3.3V and 5V readings, then yes, I would hook them up and try it out to see if it works.

Good luck.
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post #1462 of 1560
10/5/08 at 4:28pm
Quote:
Originally Posted by ludoo View Post
I would think you would want to use the green Capacitors (Muse ES) as output caps, not the blue and gold (Panasonic FC) ones.
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post #1463 of 1560
10/5/08 at 4:35pm
Quote:
Originally Posted by MisterX View Post
I would think you would want to use the green Capacitors (Muse ES) as output caps, not the blue and gold (Panasonic FC) ones.
Oh right. Late night DIY always sucks, especially if you are a noob. Thanks a lot for spotting it.
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post #1464 of 1560
10/5/08 at 7:49pm
Quote:
Originally Posted by Pars View Post
The PCM will take some abuse, but hard to say. I rebuilt a users Alien (transferring all parts to a new board), and applied heat longer than recommended when removing the PCM from the old board. It still worked.

I didn't catch what you meant about D+ and D- until I reread that you are panel mounting the USB jack. If you have proper 3.3V and 5V readings, then yes, I would hook them up and try it out to see if it works.

Good luck.
oh... my... lord...
Guess what the problem was.

Quote:
Jumper S1a and S1b or use a SPST switch
..
..

........................................
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post #1465 of 1560
10/5/08 at 8:02pm
I almost forgot to jumper that too. But right before I plugged it in I remembered.
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post #1466 of 1560
10/6/08 at 2:29am
So I'm measuring 4.9v at the input of the reg101ua, but I'm getting only 0.26v out.

I've checked every single connection around the regulator, and everything looks to be ok. I thought maybe r31/r32 values might be off, but the resistance oscillates
The markings and my BOM however show 11.81k at r32 and 31.62k at r31.
I've spent over an hour trying to debug it, but theres not really much circuitry to look at.

Any suggestions?

Also, can I temporarily jumper between the AU+ and 5v pad, or will that hurt the components?
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post #1467 of 1560
10/6/08 at 3:26am
Quote:
Originally Posted by JamesL View Post
So I'm measuring 4.9v at the input of the reg101ua, but I'm getting only 0.26v out.
There's almost certainly a short somewhere. Look again .
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post #1468 of 1560
10/6/08 at 4:31am
Quote:
Originally Posted by error401 View Post
There's almost certainly a short somewhere. Look again .
I feel ashamed to call myself a diy'er... but oh how sweet victory tastes..

No short. I just forgot to solder on one of the soic-8 pins..
ADD + caffeine does not make for a safe soldering environment.
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post #1469 of 1560
10/25/08 at 1:12pm
is there any degradation to audio quality if i turn down the volume in the windows volume control to a value lower than 100? Cause when i connect it to my AMB Mini^3, its really loud on my ATH-AD700 with even a very small turn on the knob of the potentiometer.

also, will it cause any problems if i run my desktop speakers (Logitech Z-2300) off the alien dac? since its connecting to an amp within the speakers it should be ok, right?
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post #1470 of 1560
10/25/08 at 2:12pm
if you can't hear a degradation, then there aint much of one
Shouldn't be a prob with the speakers.
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