[odoe]

I'm trying my hand at an Alien DAC after building my first cmoy. I watched tangents surface mount soldering video and read up on the assembly guide here.

I just got the PCM2702 in trying to use the technique here.

I had some trouble as maybe I didn't use enough flux and had bridges, so via some links on the assembly sight, I tried cleaning them up with soldering braid, lots of it, which looks like it has worked. No visible bridges, but also doesn't look like there is much if any solder on the pins, but the sucker won't budge.

Anyway, this may sound like a dumb question, but the assembly guide says to double check with a multimeter. Now when I do this, do I use OHM mode and should I get a zero reading if I check from pin to pin?

Looking at the schematic, it looks like I should, but I'm not sure what is happening in the chip. Right now I get like 0.8 to 0.95 ohms on some, or I get about 0.9 ohms and then it goes to 0. I'm just using a cheap radio shack multi though.

These surface mounts are tricky little suckers. Once I get past this one, I think the rest will be easier.

Thanks.

 

[achina]

Check if your meter has a continuity check feature. Use that instead. It will beep when there is a closed circuit. So you don't need to watch the display.

Some flux is conductive. You should clean it off before powering the circuit. You are probably dealing with 3 different types of flux. Flux in the solder core, flux you pasted on, and flux embedded in the desoldering braid. So who knows what is in the residue.

There doesn't need to be very much solder to hold the chip on. If you put flux on the pads before you put the chip down then some solder should have flowed under the pins and have a solid connection.

One thing to try is to take a nice straight piece of wire (like a resistor lead) and slide it under the pins. You should be able to slide it all the way through easily. If there are solder bridges on the back side it will get caught on them.

 

[odoe]

Thanks a lot!
I tried the resistor lead thing and one side was clean, the other it got jammed halfway through. Well after, some more solder braiding fun and some old fashioned elbow grease I knocked a chunk of solder that had gotten jammed in there. The rest, I would say wasn't a cakewalk, but not as hard as the first one.

In the end though, I have a working Alien DAC on my first try. I'm pretty proud of myself!

Thanks!

 

[error401]

Nice work! That SSOP chip is a pain - but it's still easier than the TQFP variant