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Alien DAC v1.1 Construction Thread - Page 75

post #1111 of 1560
3/27/08 at 2:45pm
Quote:
Originally Posted by Pars View Post
Look the board over under magnification (both sides) looking for solder bridges or no connection. Take your DMM and verify that pins are actually connected to the PCB as well.
nothing jumps out at me. I have re soldered and removed some solder, but everything looks ok.
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post #1112 of 1560
3/27/08 at 3:35pm
Well, then that leaves the 2nd part... ohm it out.
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post #1113 of 1560
3/27/08 at 5:26pm
Quote:
Originally Posted by Pars View Post
Well, then that leaves the 2nd part... ohm it out.
the ics solder joints check out good
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post #1114 of 1560
3/27/08 at 5:34pm
What do the voltage test points look like? OK?
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post #1115 of 1560
3/27/08 at 5:41pm
Quote:
Originally Posted by Pars View Post
What do the voltage test points look like? OK?
I get this immediately upon connection to usb. No voltage. I tried taking pics of pcb, but my old camera won't take a good picture of the small board.
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post #1116 of 1560
3/27/08 at 7:30pm
There is a 3.3V and a 5V test point on the board. You use your meter (DMM) to test this. If you do not have at least the 3.3V, you won't get power on the PCM2702, and it won't be recognized.

Alien DAC - Assembly

See the Test the DAC section...
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post #1117 of 1560
3/27/08 at 7:55pm
Double check your regulators, I had the same thing when I accidentally switched them.
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post #1118 of 1560
3/27/08 at 8:23pm
Here are some pictures. Maybe someone can spot the issue.






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post #1119 of 1560
3/27/08 at 9:01pm
Nice quality 3rd photo, it looks like you have a some cold joints. Get some desoldering braid in there and make them wet and shiny looking. Not positive, but it looks like one of the legs on the 5V regulator is lifted, want to resolder to make sure of that one.
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post #1120 of 1560
3/27/08 at 9:38pm
Quote:
Originally Posted by FallenAngel View Post
Nice quality 3rd photo, it looks like you have a some cold joints. Get some desoldering braid in there and make them wet and shiny looking. Not positive, but it looks like one of the legs on the 5V regulator is lifted, want to resolder to make sure of that one.
Agreed. You might check that C32 on the back side, too - it looks shoved over a bit too much on the pads - might not be making contact. C12 looks like that, too, although that one's probably not enough to cause your error message. IOW, FallenAngel's suspicion about the 5V reg seems to be a good one.

Your PCM soldering looks pretty good.
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post #1121 of 1560
3/27/08 at 9:39pm
Cronic,
I have found pins 3 and 4 of the regulators hard to solder as they are connected to the ground and the heat gets sucked away too fast to get a good solder joint.

I notice some of your joints has solder whiskers which does indicate your soldering iron is not quite hot enough. This is often due to using a low watt iron.

Hope that was helpful.
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post #1122 of 1560
3/27/08 at 10:45pm
I re flowed all the joints on the pcb. I still have the same error when connected to xp pro sp2 machine and no voltage. When I hook to a vista home premium machine no errors or pop ups and no voltage. Also L12 gets very very hot when connected to computer! do the ic2 and ic3 regulators look like the are in the correct position. I also don't have outputs soldered on yet and assume that would not cause an issue? I'm confused






I'm using this to solder
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post #1123 of 1560
3/27/08 at 11:15pm
OK, lets try something different - cut (or desolder) that S1 jumper, connect a 9V battery to AV+/G2 and measure voltages again. If windows is crapping out on recognition, the PCM might be blown. L12 might be getting really hot if it was having a HUGE current being sent through it, which is what windows is saying. Hmm... come to think of it, use a safe battery like NiMH/Alkaline, NOT lithium.

Note: Also, 720F is pretty hot for SMC work, you sure you didn't cook that PCM?
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post #1124 of 1560
3/27/08 at 11:32pm
I have not soldered on the pcm2702 at all, it was pre soldered. I tried a 9v as you said and i measure 0v between the 3.3 and 5v pads and g1.
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post #1125 of 1560
3/28/08 at 12:17am
Quote:
Originally Posted by cronic View Post
I have not soldered on the pcm2702 at all, it was pre soldered. I tried a 9v as you said and i measure 0v between the 3.3 and 5v pads and g1.
Whoops, sorry, keep S1 jumpered

This still doesn't explain why you get nothing out of those voltage regs though. Do they get warm at all?
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