[particleman14]

well since the pcm2707s are out for a bit looks like this project is on hold for now..I don't mind though as the parts are cheap.. and i view these builds as more a learning experience with the added bonus of awesome functionality..

 

[cobaltmute]

Try the following to check on the chips as well, as looking straight down can miss bridges:

Select an edge of pins you want to look at (say the WM8524)
turn the board so that the pin are perpendicular to your board (running away from your body)
Slowly drop the edge of the parallel side of the board, so you start looking down between the pins onto the body of the chip.

I've had bridges that they only way you could see them was by doing this as they were behind the pins and not obvious.

 

[particleman14]

ya i've looked at it from this angle as well.. as far as I can tell there are no bridges..

 

[tomb]

Quote:

Originally Posted by ovrclkd /img/forum/go_quote.gif No Voltage at 3V3 .... short somewhere? I was looking at the vias holes, must be a dozen or so... here's some pix, maybe something will jump out to the trained eye. You'll see I chose to mount C9 vertically when I reflowed it due to lack of room. Thanks for your help! Please excuse my solder skills ... I'm still learning! <IMG]http://i251.photobucket.com/albums/gg317/ovrclkd17/Audio/IMG_1782.jpg[/IMG> <IMG]http://i251.photobucket.com/albums/gg317/ovrclkd17/Audio/IMG_1781.jpg[/IMG>

Your PCM and WM chips look OK - I can't see any bridges (where there's not a connecting via, anyway). I suspect the TPS chip on the back, though. In your back photo, the pin at the top left of the TPS chip looks a bit dodgy. That may also explain the lack of 3.3V at the test pad, too.

Just a guess ...

 

[particleman14]

editt

 

[ovrclkd]

Quote:

Originally Posted by cobaltmute /img/forum/go_quote.gif ovrclkd, Your L3 looks a little weird. Can you check the resistance across it? It seems different than L1 and L2. You C9 and C14 also look a little different.

I read zero ohms on L1,2&3 unplugged. Connected to PC is L1= 1.1 ohms, L2=1.1 & L3 is 0.2

Quote:

I would suggest that you get used to using a lot less solder. There is a lot of blobs.

You sir are too kind ... that is less solder ...lol (sorry)
I have the same loupe and everything "appears" ok.
The parts were bought off the BOM from digikey so they should be correct.

Quote:

Your PCM and WM chips look OK - I can't see any bridges (where there's not a connecting via, anyway). I suspect the TPS chip on the back, though. In your back photo, the pin at the top left of the TPS chip looks a bit dodgy. That may also explain the lack of 3.3V at the test pad, too. Just a guess ...

Thanks for the suggestion Tom, I reflowed that leg but still no voltage at the 3v3.

Something for you both ... when I run a meter from the 5v to 3v3 it reads 5 volts, same if I test from 5v to D-, D+, & 0V

C14 is 5ohms & C9 is 9 Mohms

 

[ziplock]

I wanted to bring up a parts issue with the current BOM of the GrubDAC.

If you opt for the standard C5, C15 330uf 6.3V, 2.5mm ls,6.3mm dia max, 11.2mm high2Mouser647-UHE0J331MED caps instead of the C5, C15 alts, the hammond case will not close properly. The 11.2mm height of these caps is too much. I had to drill two appropriately sized holes in order for the top to screw down flush.

Just FYI...

 

[tomb]

Quote:

Originally Posted by ziplock /img/forum/go_quote.gif I wanted to bring up a parts issue with the current BOM of the GrubDAC. If you opt for the standard C5, C15 330uf 6.3V, 2.5mm ls,6.3mm dia max, 11.2mm high2Mouser647-UHE0J331MED caps instead of the C5, C15 alts, the hammond case will not close properly. The 11.2mm height of these caps is too much. I had to drill two appropriately sized holes in order for the top to screw down flush. Just FYI...

Yep - sorry that this tripped you up. I'll edit the BOM when I get a chance. In the future, the 560uf org-poly at DigiKey will be the primary choice we'll recommend. Those will be the ones included in the kits, too. The 220uf org-poly at Mouser and Beezar will also work, but you have to ensure that you solder them down as tightly to the board as possible. Those are the ones I used in my proto CableDAC builds, but I doubt there's enough room between the tops and the inside of the lid to slip a piece of paper in-between.

 

[cobaltmute]

Quote:

Originally Posted by ovrclkd /img/forum/go_quote.gif C14 is 5ohms & C9 is 9 Mohms

C14 show that there is an issue. There should be greater than 5Ohms between the positive rail and the negative rail.

I'm guessing you used the Digikey BOM? Looking at your parts, and the BOM, I have discovered an issue. C9 and C14 in your build appear to 1206 parts. They should be 0805. The issue is with the BOM as during the development process we changed the size and changed the Mouser part, but not the Digikey one.

Somewhere on your board, there is a bridge from the positive rail to ground. Follow the traces from the 3v3 point and check all the pins that are attached to it for connectivity to ground. You'll have to do this by eye as all the pins are in parallel, so the reading should be the same.

 

[ovrclkd]

Quote:

Originally Posted by cobaltmute /img/forum/go_quote.gif C14 show that there is an issue. There should be greater than 5Ohms between the positive rail and the negative rail. I'm guessing you used the Digikey BOM? Looking at your parts, and the BOM, I have discovered an issue. C9 and C14 in your build appear to 1206 parts. They should be 0805. The issue is with the BOM as during the development process we changed the size and changed the Mouser part, but not the Digikey one. Somewhere on your board, there is a bridge from the positive rail to ground. Follow the traces from the 3v3 point and check all the pins that are attached to it for connectivity to ground. You'll have to do this by eye as all the pins are in parallel, so the reading should be the same.

NUTS ...... I JUST SOLDERED TWO MORE OF THOSE ON ANOTHER BOARD!

The first board has had them off twice ... I'm having a hard time getting the solder to stick to the pads.
I purchased 98% of these parts from the DK BOM (three kits worth) .... PLEASE review the rest of it.

THIS EXPLAINS WHY THE SMD'S ARE WIDER THAN THE PADS!
Back to de-soldering .......

 

[tomb]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Yep - sorry that this tripped you up. I'll edit the BOM when I get a chance. In the future, the 560uf org-poly at DigiKey will be the primary choice we'll recommend. Those will be the ones included in the kits, too. The 220uf org-poly at Mouser and Beezar will also work, but you have to ensure that you solder them down as tightly to the board as possible. Those are the ones I used in my proto CableDAC builds, but I doubt there's enough room between the tops and the inside of the lid to slip a piece of paper in-between.

Maybe I accepted fault too quickly.

Please note that 10.5mm is an accurate height clearance. However, quality electrolytics may have a rubber plug that causes them to exceed this height. The organic-polymer caps do not have as much of a plug and so the installed height is much less. That said, I have removed everything but the organic-polymers from the BOM. Standard electrolytics will work, but you are on your own with clearance using the Hammond 1551HTBU. We recommend the 560uf org-poly from Digikey as the primary choice (will also be available from Beezar and in the kits). It's only 10.5mm high.

 

[tomb]

Quote:

Originally Posted by ovrclkd /img/forum/go_quote.gif NUTS ...... I JUST SOLDERED TWO MORE OF THOSE ON ANOTHER BOARD! The first board has had them off twice ... I'm having a hard time getting the solder to stick to the pads. I purchased 98% of these parts from the DK BOM (three kits worth) .... PLEASE review the rest of it. THIS EXPLAINS WHY THE SMD'S ARE WIDER THAN THE PADS! Back to de-soldering .......

Sorry about that. It doesn't make you feel any better, I'm sure, but I had to mess with the same thing on both of the ones I built. I ordered C9 and C14 from Mouser when both were listed in the 1206 section of the BOM. I corrected it after that for the Mouser parts, but apparently missed it on the DigiKey column. This is really no excuse, but cobaltmute and I went through 6(!) revisions during design and prototyping. I was attempting to keep up each time with a revised BOM, but missed a couple of things along the way. The design has been "locked" for some time now, so there shouldn't be anymore changes. I guess some of you have still been acting as prototypers for the production version, in a way. Again, please accept my apologies.

Please note that this has been corrected and some other major changes made to the BOM on the grubDAC website:
GrubDAC BOM

These changes bring the BOM up-to-date with the latest pricing and more closely aligns the parts listing with the kit options that we'll be offering.

NOTE: As always, if a BOM is linked to a specific part that is out-of-stock, please do a search on Mouser/DigiKey using the BOM description. Except for the IC's, there are many other parts available. Cobaltmute and I simply selected the parts with the lowest price and highest stock number at the time the BOM was first formulated. I make an attempt to update pricing from time to time, but some of these SMD passives can run out of stock in a day's time, depending on manufacturing product pressures in the industry.

 

[ovrclkd]

No worries ... always a learning process.

Thank you both for catching this and making the necessary changes.
Everything happens for a reason ..... I'll order the correct parts and more solder

and hopefully have a grubDAC in working order for the MAX!

Enjoy your Sunday guys .... I'm off for a spin!

 

[ziplock]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Maybe I accepted fault too quickly. Please note that 11.2mm is an accurate height clearance. However, quality electrolytics may have a rubber plug that causes them to exceed this height.

That's one hell of a plug. The caps are almost flush with the top of the case after drilling.. lol

Judging from the Nichicon DS, the length is measured top of cap, to plug, not just the cylinder housing alone.

Anyway, at this point it's a non issue. I'm probably the only one who went with the ghetto caps.

 

[tomb]

Quote:

Originally Posted by ziplock /img/forum/go_quote.gif That's one hell of a plug. The caps are almost flush with the top of the case after drilling.. lol Judging from the Nichicon DS, the length is measured top of cap, to plug, not just the cylinder housing alone. Anyway, at this point it's a non issue. I'm probably the only one who went with the ghetto caps.

... and I was wrong (again?) - the clearance height is 10.5mm, not 11.2mm. Again, please accept my apology - the BOM has been corrected with caps that will fit.