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pupDAC Step-by-Step Build Thread - Page 13

post #181 of 277
Thread Starter 
Quote:
Originally Posted by lithoras View Post
 

Hey guys,

 

So I build my pupdac, and all the voltages are correct expect one. The 3.3 v at U4 is a 2.02. Now I am not sure wether the chip is damaged or some capacitor somewhere. I reflowed all the joints from J1 to the checkpoint so I think something is damaged. I just don't know what it is. Can someone pls give the correct voltages of the C13, L1, C4, C7, C5, C1 and the X1 output. 

 

 

 

P.S. the chip is recognized by windows, however the right channel does not work, I get clean audio from the left channel though.

 

 

O and it seems that my U5 is heating up like crazy, I burned my finger when I touched it, after it was on for a couple of secs.


Pics.

 

Your issue is really with U5, I suspect.  It may be drawing down the overall voltage of the USB bus.  U4 is low, but apparently there's enough there for the computer to recognize it.  U4 supplies the voltage for the PCM2707, which controls the USB connection.*  Are there any bridges on the U5 chip?

 

Pics. ;) 
 

* EDIT: I don't think the PCB would recognize it, otherwise.


Edited by tomb - 2/13/14 at 5:49pm
post #182 of 277

The incoming voltages on U4 and U5 are both 4.99 V yet both their outputs are off, u might be right cause indeed the U5 voltage check is high, I checked if there are any bridges via backlight on the pcb and there are none. I can't take pictures sinse I am a student and don't own a proper camera XD. 

What is also interesting is that if I apply a small torque on the pcb I get stereo sound but the voltages don't change. the torque is equall to holding the long sides of the pcb and pushing in the middle on the J1 half of the pcb. The applied pressure is minimal.... I honestly don't know what that means XD

 

* EDIT: oke so my U4 just broke down, I know this to be very true, cause well, it doesn't let any current through any more


Edited by lithoras - 2/14/14 at 1:41pm
post #183 of 277
Thread Starter 
Quote:
Originally Posted by lithoras View Post
 

The incoming voltages on U4 and U5 are both 4.99 V yet both their outputs are off, u might be right cause indeed the U5 voltage check is high, I checked if there are any bridges via backlight on the pcb and there are none. I can't take pictures sinse I am a student and don't own a proper camera XD. 

What is also interesting is that if I apply a small torque on the pcb I get stereo sound but the voltages don't change. the torque is equall to holding the long sides of the pcb and pushing in the middle on the J1 half of the pcb. The applied pressure is minimal.... I honestly don't know what that means XD

 

* EDIT: oke so my U4 just broke down, I know this to be very true, cause well, it doesn't let any current through any more


Torque and applied pressure are sure signs of inadequate solder joints, I'm sorry to say.  I can't speak to the rest of it unless you are able to supply pics.

 

You might try re-flowing everything.  I had another builder misinterpret that, so please read carefully.;)  Please don't think that I'm that I'm suggesting that you add more solder to everything.  No more solder - simply turn up the heat (slightly) on your iron and try to re-melt every joint until it is completely melted and is "perfectly mixed" when you remove the iron.  If you have an iron that is not temperature-adjustable, then perhaps wait a number of seconds (or a minute) between each joint before re-applying the heat from the soldering iron.  You must completely re-melt every joint and then ensure that the solder joint stays that way while you remove the iron.  That's what re-flowing solder joints means.

 

Short of that, try to get some decent solder (63/37 eutectic) or a soldering iron that allows some heat adjustment.

 

Lastly, try to get someone who can take some pics. :) 

post #184 of 277

all right so I did that.

I used this iron, http://www.conrad.nl/ce/nl/product/588666/TOOLCRAFT-ST-50A-Toolcraft-analoog-soldeerstation-50-W-Vermogen-50-W 

    I turned it up from 280-300 degrees

and a solder of Sn60Pb39Cu1

I re heated all the joints and checked for bridges --> no bridges, I think it is solid.

that was the point on which my U4 broke down, at least I think. Because well the 3.3V is went a 0 and the 4.5V is a 4.95. That was the time I edited my post ;) 

I'll try to fix some pictures today.

post #185 of 277
Thread Starter 
Quote:
Originally Posted by lithoras View Post
 

all right so I did that.

I used this iron, http://www.conrad.nl/ce/nl/product/588666/TOOLCRAFT-ST-50A-Toolcraft-analoog-soldeerstation-50-W-Vermogen-50-W 

    I turned it up from 280-300 degrees

and a solder of Sn60Pb39Cu1

I re heated all the joints and checked for bridges --> no bridges, I think it is solid.

that was the point on which my U4 broke down, at least I think. Because well the 3.3V is went a 0 and the 4.5V is a 4.95. That was the time I edited my post ;) 

I'll try to fix some pictures today.


OK - looks like we have a language difference as well, because I don't understand a few sections of your post.

 

Pics will help, for sure.

post #186 of 277

Hi folks, quick question about the pupDAC - since this thread is relatively recent and cobaltmute's thread is from November, I'm posting here - is the volume controllable via Windows volume control, or is it locked at 100% volume no matter what Windows shows, a la GrubDAC? Thanks!

post #187 of 277

oke so it took me a while (work and being sick and stuff), but I finally got some decent pic's to show u. 

http://i125.photobucket.com/albums/p57/lithoras/DSC_00351_zps280cdc29.jpg

 

due to a spot on the lens it seems as if there is a bridge on U2, this is not the case. 

there is a bridge on the left side of U3 between pin 3&4, as wel as on U8. These bridges however match the scematics of the board (they should be connected) airgo I did not put any effort into removing them.

I hope you can find a problem I can solve, otherwise I think I should order a new U4 since it's output voltage is 0

post #188 of 277

So I finally managed to make a decent picture. 

 

"http://i125.photobucket.com/albums/p57/lithoras/DSC_00351_zps280cdc29.jpg"

(due to a particle on the lence, it seems as if U2 has a bridge. This is not the case!!)

 

I hope you can find a problem which I can solve, otherwise I'm afraid I need to order a new U4 since it's output voltage is 0.

 

P.S. u can see 2 bridges, one on U3 on the left side on pin 3&4 and one on U8. These however match the schematics of the board (meaning the pins should be directly connected) so I did not put any effort into removing them. 


Edited by lithoras - 2/24/14 at 2:54am
post #189 of 277
Thread Starter 
Quote:
Originally Posted by lithoras View Post
 

So I finally managed to make a decent picture. 

 

"http://i125.photobucket.com/albums/p57/lithoras/DSC_00351_zps280cdc29.jpg"

(due to a particle on the lence, it seems as if U2 has a bridge. This is not the case!!)

 

I hope you can find a problem which I can solve, otherwise I'm afraid I need to order a new U4 since it's output voltage is 0.

 

P.S. u can see 2 bridges, one on U3 on the left side on pin 3&4 and one on U8. These however match the schematics of the board (meaning the pins should be directly connected) so I did not put any effort into removing them. 


Yes, U3 has those pins bridged, anyway.  U8 has a couple bridged, too, but U8 is out of the range of your photo.

 

I'm a bit worried with U2 in its appearance in the photo.  The rest seems to look OK on first glance, although most of the solder joints appear to be cold.

post #190 of 277

oke.... So what do u suggest I do, I reheated every joint (put the iron on the pin, waited like 2-3 seconds) and u say the'r still cond :/  oke could be, I'll turn up the iron even further..... And it appeared to be working except for the right channel, me reheating those joints did not help. Reheating them a second time, caused me to burn in U4 (I think) since it's output voltage is now 0....

I really don't know what to do anymore :S

 

(I'll try making another picture this afternoon, from which u can tell the state of U2... it actually looks similar to U5 on the eye)


Edited by lithoras - 2/25/14 at 12:11am
post #191 of 277
Quote:
Originally Posted by Ikarios View Post
 

Hi folks, quick question about the pupDAC - since this thread is relatively recent and cobaltmute's thread is from November, I'm posting here - is the volume controllable via Windows volume control, or is it locked at 100% volume no matter what Windows shows, a la GrubDAC? Thanks!

 

It's like the GrubDAC.

 

-chris

post #192 of 277
Thread Starter 
Quote:
Originally Posted by lithoras View Post
 

oke.... So what do u suggest I do, I reheated every joint (put the iron on the pin, waited like 2-3 seconds) and u say the'r still cond :/  oke could be, I'll turn up the iron even further..... And it appeared to be working except for the right channel, me reheating those joints did not help. Reheating them a second time, caused me to burn in U4 (I think) since it's output voltage is now 0....

I really don't know what to do anymore :S

 

(I'll try making another picture this afternoon, from which u can tell the state of U2... it actually looks similar to U5 on the eye)


Cold joints don't necessarily mean it was a cold iron.  Lack of flux, the wrong solder, or the wrong kind of tip on the soldering iron can all cause it.  In some cases, it may be that you need to use some de-soldering braid to clean between the pins.

 

Yes, you're correct that the angle of the photo might've caused me to suspect U2.

 

Try to clean the PCB as best you can, clean up those solder joints (not necessarily by turning the heat up), and use an X-acto knife between the PCM chip pins, if you can.  Then tell us again what you measure on all of the voltages.  However, don't do that if something gets hot - measuring the voltages aren't more important than preserving the parts.

 

Just an FYI, but I typically adjust to 325 deg. C. or slightly higher for SMD work.  I'm using a very small tip (0.8mm chisel), though, so you have to weigh that against a larger tip size which will distribute the heat faster. 

 

EDIT: :confused: deg. C.!  not F! - dang it!


Edited by tomb - 2/26/14 at 3:00pm
post #193 of 277
How long can and or should the board be soaked in alcohol for to get the flux off?
post #194 of 277

I don't soak boards, just lay into it with an old toothbrush and blot dry with a wad of tissues, do that twice and all the flux will be gone

 

cheers

FRED

post #195 of 277

I would like to say that I replaced U4 with a new chip I ordered, and the board now works as it should. All the voltages are correct just as the stereo sound (I however have a bit of noise coming from my tweeter. I can hear it at about 10 cm away from it.... any ideas where it might come from? or is it inherited tot the pupdac??)

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