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Y1 capacitor question - Page 2

post #16 of 28
8/7/11 at 5:30pm
Quote:
Originally Posted by shrimants View Post


I'll take your advice and test for ohms between Y1 and Y2's pin/receptacle, I cant believe i didnt think of that.
 

I'm not questioning your abilities at all, because we all make simple mistakes, but you are switching the multimeter back and forth between dcv and ohms when you are taking the various measurements, correct?

 

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post #17 of 28
8/7/11 at 5:46pm
Thread Starter 
yes, that much I am doing correctly, no offense taken.

The multimeter I am using looks like this http://www.paranormalghost.com/equipment/Radio%20Shack%20Digital%20Multimeter%2022-810.jpeg

it is by no means a good one and I wouldnt be surprised if it was broken. I borrowed it from my friend so I wouldnt have to be stuck using a 5 dollar analog one my dad bought. I'm seriously considering just going out and buying a decent 50 dollar one, especially considering I'll be doing more projects in the future.

The ohms setting just says 200 to denote the scale is 1 ohm, but as I said, the meter only shows 0L when I tested a 560 ohm resistor. If I set the meter to "2k" it will read .560, which is correct. Similarly, for voltage I set it to the "20V" mark to set the scale to 1 volt, but even the USB input when plugged in only shows me .871 volts.....

I'm convinced the multimeter is broken.
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post #18 of 28
8/7/11 at 9:25pm
Quote:
Originally Posted by shrimants View Post
The ohms setting just says 200 to denote the scale is 1 ohm, but as I said, the meter only shows 0L when I tested a 560 ohm resistor.


200 ohms is the range for that setting. 560 > 200 therefore reads as out of range.

 

As for the voltage setting - measure a 9V battery and/or a 1.5V cell to check the meter - in circuit there could be other things messing with your readings.

 

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post #19 of 28
8/8/11 at 8:10am
Thread Starter 
Good thinking. Also, i definately did not know that about the meter......I feel kind of like an idiot, but then again i'm used to those giant behemoth super meters that my school has.
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post #20 of 28
8/8/11 at 8:35am
Thread Starter 
Alright, the problem was me, not the meter. Since I didnt realize that the number printed is the range the multimeter will read, I was reading it wrong. Now that I have been enlightened as to The Way of The Multimeter, here are my voltage measurements on the Y2. My readings are in blue.

I used the TPS7934 for U1 and according to the site, I should be reading 4.75 ish volts. This worries me. I'll see if I can figure out any other tests and if I get my parts in today I'll build that test cable to see if the Y1 F++ works as stand alone.

500
Edited by shrimants - 8/8/11 at 8:39am
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post #21 of 28
8/8/11 at 1:28pm

With the meter set to the lowest range measure the resistance between the top of X1 and each of the pads highlighted in red.

(the readings should all be "OL")

 

X1.jpg

 

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post #22 of 28
8/8/11 at 1:34pm
Thread Starter 
Done. They all read 0L. Just for kicks I measured the resistance between the one you didnt highlight and the top of the X1 and it measured 0 ohms. It looks like I bridged the pads to the top of the X1 but I think thats just some discoloration or soemthing....
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post #23 of 28
8/8/11 at 2:37pm

U4 is next but the image you have provided makes it hard to tell if what are apparent problems are actual problems or something else.

 

In either case a little spot de-fluxing (with a swab) won't hurt. ;)

 

U4.jpg

 

 

 

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post #24 of 28
8/8/11 at 2:50pm
Thread Starter 
Am I checking for resistance in those gaps or am I defluxing those gaps? I used drag soldering for that part so I dont know how well it worked....
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post #25 of 28
8/8/11 at 3:57pm
Thread Starter 
Here are closeups. I cleaned up the chips a bit on the Y2. This is the best my measly point and shoot can muster up. The actual size image is rather fuzzy.

I looked through my 15x loupe to see if there were any bridges or something. THere was this weird white residue that I cleaned up and then I went through and reheated the solder just incase there was a cold joint somewhere. Still no luck.

500
500
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post #26 of 28
8/9/11 at 1:52pm
Thread Starter 
UPDATE:

Got that switch in the mail today. Managed to rip up one of the traces to it while attempting to clean up the holes. my desolder wick BLOWS, and refused to pick anything up, same with my soldering iron. In any case, I managed to do a really really ugly fix using a random copper wire clipping. It looks like crap but only reads a 0.1 ohm resistance, so without having to redo the entire y1 this is the best I can muster up.

In any case, I also made a jumper cable to connect
J2U pin 1 (VBUS) -> J4D pin 1
J2U pin 2 (VCC) -> J4D pin 2
J2U pin 3 (GND) -> J4D pin 3
J3U pin 1 (GND) -> J5D pin 1
J3U pin 5 (DATA) -> J5D pin 5

It successfully powers the DAC board. The 4.5v test pad reads about 4.3V, all the 5V test pads on the USB board are reading 4.9V. Unfortunately, the 3.3V test pad is only reading 0.5 volts, so thats likely where the problem is.I went through and touched up anything that even remotely looked like a cold joint but I cant get it to work. The light on the bicolor switch remains red and there is no sound from the Y1 standalone. Hope that helps people diagnose what is up.

Also, MisterX, I see you are also in michigan. It lists you as a builder on the Y1 page. Would it be possible for me to give you the y1 for fixing (assuming I cant figure anything out myself) for monetary compensation or do you only build them from scratch?
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post #27 of 28
8/9/11 at 5:00pm
Thread Starter 
UPDATE 2

Did some scouring on the AMB forums and found that a faulty 3.3v test pad on the Y1 is almost 100% of the time related to a faulty U5D. I reflowed that chip, put my temporary ghetto jumpers on, and BAM. Y1 is recognized. Unfortunately, now the Y2 is compltely unrecognized whereas before it was fine.....wtf....

Also all of my voltage readins are fine for the Y2 so it doesnt make any sense. I'm going to test adjacent pins on the chips and also test for cold joints and see if that fixes anything.

Update 3

Y1 works just fine except for a bit of distortion (probably caused by windows). there are artifacts in the low frequency range which I am not a fan of. It could be that my A5's are incapable of amplifying those frequencies or it could simply be that the test file I found was messed up.

The Y2 is completely ignored by the system though, while plugged in I only get sound from the Y1 headphone jack.....Any ideas?
Edited by shrimants - 8/9/11 at 7:37pm
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post #28 of 28
8/10/11 at 10:46am
At this point, with no power applied, you will need to check for shorts between the pins of the various ICs as well as verify continuity between the various points of the schematic. For SMD chips this small, you really need needle points for your multimeter probes. You can make them using sewing pins if you do not have them (tape or clip the pins to the probes).

When I built my y2, I had two problem areas:

1) A short between pins 13 and 14 of U4 that applied the mute function of that chip.

2) A cold solder joint on either pin 2 or 3 of X1 which prohibited the clock reference from being generated (and/or propagated) across the board.

I would certainly start with X1 and U4 as they seem to be the most problematic. I think misterX was trying to lead you in that direction. There are no short cuts at this point. Just diligent checking of each solder joint on the board.
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