But all of the parts on the SDR-Cube are fairly benign and totally stick solderable. Because the sr63ng (build instructions here) had SMT parts on both sides, and I was feeling guilty about scaring George Heron and maybe his customers off... I decided to completely stick solder the unit. No problemo, dude. This board has TSSOP's on it, like the CODEC on the SDR cube. Really easy to do with the flux, roll solder ball and (if needed ) solder wick off. Being nearly 100% SMT it was faster to build than the same circuit portion of the Ensemble.
SMT Stick soldering review here: flux the part (including caps and resistors.. everything) liberally. Put a small ball of solder on the opposite side of the IC than you are handed... I.E. if you are right handed go from left to right. Roll the small ball across all pins (don't touch the pins hard when rolling the ball--or at all if possible)-- avoiding adding more solder for as long as possible. At the end try to pull the remaining ball (bridge) off of the pins by drawing the solder from the IC package towards you. If that doesn't work do the same motion with some solder wick. Fluxing the solder wick isn't a bad idea either when doing this. DO NOT draw the wick across the pins like you did the solder ball.. particularly with finer pitch parts like the TSSOPs. You can easily bend the pin into the next one over and it's a BEAR to fix as you have to either hot air remove the part or contend with reforming the pin with a hot soldering iron. Always, ALWAYS wick from the package to you.
Anyway.. you can see that the stick solder SMT job is good.. but some of the parts are a little crooked compared with the "surface tension self centering" of the griddle reflow. But these are 100% okay and reliable. It's suggested that the SDR-Cube be built this way by it's creators and it's low risk that way.
Here is the sr63ng topside The side mounted cap, unfortunately is a small demerit for George in Canada.. of all things I was short one 16V leaded electrolytic. I only stock 35V parts in my junque box:
Again, notice that cleanliness is next to godliness when it comes to building PCB's up. I again insist that you must de-flux the boards to make sure that you don't have questionable solder joints and/or bridges. It is even more important when stick soldering because you used a lot of flux when doing this.. DIDN'T YOU?!? Notice how much nicer and professional the mostly SMT board looks compared to the Softrock Ensemble RXTX (which looks more like a Japanese transistor radio from the 70's by comparison.. all of those resistors standing on end always remind me of an old AM radio.. I can't help it.).
Anyway the back side of the board is also used... here is a picture of this. Some day I need to wire up a convection toaster oven and a PID controller so I can go paste/reflow on two sided boards like this.
Looks pretty good. Keep your building neat.. it's worth the nominal extra effort.
Because of the design of this board.. the Si570 needs external I2C control.. it's not really worth testing this beast until I have the SDR-Cube DSP board going and probably not until I have the RXAMP and PA built for it. Hopefully all will go well. It was actually easier to identify the chip parts on this kit (they were extremely well packed and labelled by George in Canada at Yoyodyne---- and at least for the resistors were marked with numbers( compared to those annoying no contrast 1% resistors that are in the Softrock kits. (Sorry again to Tony Parks.. regardless of the annoying toroids and resistors he is a saint providing a valuable service!). So chances are that this one will fire up right away.
Anyway.. until I receive the goods that this will be built into (the coveted SDR-Cube kit).. I'll sign off for now.
No comments:
Post a Comment