pupDAC Step-by-Step Build Thread

[scootsit]

Does the LED need to be high efficiency, as speced or will any LED work?

 

[tomb]

Quote:

Does the LED need to be high efficiency, as speced or will any LED work?

Physically, any through-hole 3mm should work.
 
Cobaltmute would need to confirm if a super-brightness, high-current LED would adversely affect the current draw and the USB connection.  The one that's spec'd is plenty bright, so I personally wouldn't go brighter than that.

 

[kyoshiro]

to be more correct, led doesnt light up and driver installation didnt start odears

 

[tomb]

Quote:

to be more correct, led doesnt light up and driver installation didnt start odears

Sorry I didn't see your first post, kyoshiro.  The LED pretty much takes its power directly from the USB connector.  There's not much else in the string except a single resistor and a ferrite.  If that indicates you're not getting proper power to the PCB, then nothing else is going to work, either.
 
Can you supply some pics?

 

[KimLaroux]

I realize this will sound like at obvious question but I feel like the problem may be the PC itself. Have you tried connecting it to another computer?

 

[kyoshiro]

welp  got the LED to light up but computer recognizes it as unknown device ffffffffff
I'll post some pics tmr after work as I had a long day

 

[kyoshiro]

https://www.dropbox.com/sh/3qkqeso6wbktmpy/B6mp5Dd6y0
 
should have them pics there.

 

[kyoshiro]

ahh failed and shared my whole camera upload folder (oops)
 
here is only the PCBs
https://www.dropbox.com/sh/8kbkzzmkqtpp2hd/WS56Y4JZnY

 

[tomb]

Quote:

ahh failed and shared my whole camera upload folder (oops)
 
here is only the PCBs
https://www.dropbox.com/sh/8kbkzzmkqtpp2hd/WS56Y4JZnY

Have you measured the voltages at the test points and can you share those with us?
 
I am particularly interested in the 3.3V test points at U4 and U1 (the PCM2707 chip).  If the computer powers the LED but does not recognize the rest of the device, something is wrong in the PCM2707 portion of the circuit - that's what negotiates all the communication with the PC and the USB connection.  If those voltages are off, the PCM2707 may not be operating properly.  U4 looks a bit suspect in its connections and there may be some bridging on U1.
 
If you can confirm those voltages, that may help to pinpoint the problem.

 

[KimLaroux]

Quote:

ahh failed and shared my whole camera upload folder (oops)
 
here is only the PCBs
https://www.dropbox.com/sh/8kbkzzmkqtpp2hd/WS56Y4JZnY

 
C25 seems shorted. C27 may have a cold joint.
 
If I were you, I'd reflow everything on the bottom. You seem to have had trouble soldering all that, did you use lead free solder?

 

[H22]

looks like there may be a few cold joints there.
 
Tomb, perhaps you might consider including a small roll of good solder, a small tube of flux and possibly a roll of solder wick with these kits?
 
Personally I don't know how I ever did SMD work without good flux (I like the stuff that chip-quick sells, but it is not cheep).
 
I know it would add to the cost of the kit, but i think in the long run it would be worth it.
 
Kyoshiro, I don't know where you are located, but see if you can get some flux (i prefer a gel type for SMD work) and some small (1/8 to 3/32 inch) solder wick before you "re-flow" your board.
 
I would coat every joint with a little flux, then heat it with the iron till it melts and turns shiny, then remove the heat. Use the solder wick to pull up excess solder if needed.

 

[tomb]

Quote:

looks like there may be a few cold joints there.
 
Tomb, perhaps you might consider including a small roll of good solder, a small tube of flux and possibly a roll of solder wick with these kits?
 
Personally I don't know how I ever did SMD work without good flux (I like the stuff that chip-quick sells, but it is not cheep).
 
I know it would add to the cost of the kit, but i think in the long run it would be worth it.
 
No offense, but these things are emphasized quite strongly - here and here and here and finally - in the very first post in this thread: here .  No offense, but most of us draw the line at putting construction tools in a DIY kit. Might as well include the tweezers and a Hakko 936, next.  I guess I'm a bit miffed at the implication that I haven't provided enough support for Beezar kits.

 
Kyoshiro, I don't know where you are located, but see if you can get some flux (i prefer a gel type for SMD work) and some small (1/8 to 3/32 inch) solder wick before you "re-flow" your board.
 
I would coat every joint with a little flux, then heat it with the iron till it melts and turns shiny, then remove the heat. Use the solder wick to pull up excess solder if needed.

 
EDIT: Just a suggestion, but maybe you guys should think a bit and use some tact before you declare that a builder is a lousy solderer.  I can't tell you how many people contact me directly through e-mail, simply because they're too embarassed to post photos of their work.  It's like stripping themselves nude in front of a camera.  Give 'em a little encouragement first ... try not to mention that their work may not look so good when they're crying for help.

 

[tomb]

Don't get me wrong - your help is greatly appreciated.  I would rather 100 times over that someone post their problems here, instead of contact me directly through e-mail or PM.  Hell, I'm no expert ... and even if I was, it wouldn't compare to having dozens of eyes look at the problem.  It's always best to post here and have you guys help.
 
Guess that comment about including more stuff with the kit set me off.  I apologize.

 

[KimLaroux]

Yeah well it's always touchy to give advice in those cases. The line between insulting someone and saying what needs to be said is blurry at best. And on the internet, it's even worse. It's not like you can use a different tone. Words are just words. You have to use a thousands words to say something that can be said in ten, just to make sure you're not insulting someone. And everybody takes criticism differently... which worsen things even more.
 
And just to be clear, I did not say he was a "lousy solderer". That would be insulting, which is not helping anyone. Besides, I've never soldering SMT chips myself, so I'm probably no better than Kyoshiro. Everybody's got to start somewhere. Nothing to be ashamed of.
 
The instructions you published for the pupDAC are amazing, the best I've ever seen. I even pass the link to people on IRC that have troubles with SMT. I think you did an exemplary work with the whole pupDAC kits, and nothing more should be asked. I agree with you that a kit should not include tools to build the kit. DIY audio is a hobby, and acquiring the tools needed for a hobby is, well, part of the hobby.
 
My comment about solder was from personal experience. The forms in which the solder cooled on Kyoshiro's board reminds me of the way lead-free solder works. Lead-free is a serious pain to work with, and as a DIY'er, I think starting with lead-free is shooting yourself in the foot. So, if Kyoshiro does in fact use lead-free, I recommend he gets 63/37, just like you recommend on the pupDAC's webpage.

 

[kyoshiro]

I'm using some 60/40 solder that I had lying around that I bought for soldering the O2, thought it would do the trick nicely as my other roll is a WBT lead-free.  But yeah first time soldering SMDs so need a bit more work here n there. I still havent had time to take the steps suggested as I have caught a cold, should get to it soon enough. Thanks for all the suggestions tho!