Tag: CC1

CC1 has a lot of toroids on it. Dave/AA7EE wound some pretty nice looking toroids for his CC1 so I asked him for some tips and tricks for winding toroids. He uses a crochet hook to pull the wire through, but also pointed me at this YouTube video showing the “chopstick method”.

It’s a pretty good way of winding toroids. The chopstick holds the toroid and lets you apply a bit of tension to the wire to get nice tight windings.

2 down, 11 more to go…

The CC1 build is back on track with the replacement U6 transistor and U4 oscillator.

I ended up completely mangling 3 out of the 5 pads that U6 is mounted on, so I had to do some creative/ugly jumpering between U6 and the components it connects to.

Pro tip: Before trying to remove a part, make sure all the solder is removed before pulling it off.

It’s supposed look like U7 on the right (maybe minus that big ball of solder on pin 4). Instead, I had to jumper across to C65 and C66 and connect pins 1 and 3 (normally connected by a trace under U6). The wire to the right connects V_out to the 3.3V test point. It looks ugly, but it works. Still getting 5V from U7, and 3.26V out of U6. For a while, I was getting a little worried that I had completely ruined things.

CC1 build is back on track. Next I need to wind some inductors for L12 and L13 to finish off the audio amp/mute stage.

Finished off the microcontroller/DDS section of the build with the installation of U5. Used the solder and wick method to put it on as suggested in the assembly guide. Used a bit of flux paste to help hold the IC down and went at it with the solder. Worked out reasonably well and I think I managed to get it on without any solder bridges.

The next section (Audio amp/mute) has more SMT and is a fairly dense section of the board. Takes some patience and steady hand to get all the components in, but by now you’re used to the ‘tack and solder’ method so it goes a little faster.

Dave/AA7EE suggested installing one of the electrolytic caps (C36) in this stage and thinking I’d be clever, I went ahead and did it early. A little too early as it turned out, because the stage also calls for the two other larger electrolytic caps (C20 and C29). C36 is right next to C29, and if C36 is there first, it’s impossible to install C29. So because I jumped the gun, I ended up having to remove C36, solder on C29 then solder C36 back on.

The last part of the stage involves putting on the connectors and switches, which is pretty easy and goes pretty quickly. Almost starts looking like a transceiver now.

Next step is to wind two inductors and put them on. Once the replacement U4 and U6 arrive, I’ll put those on and be able to test if it produces any tones.

While I’m waiting for Jason to send me a new U6 transistor, I decided to forge on ahead with the build. Lots of small SMT caps and resistors to put on, but using the ‘tack and solder’ method, it’s been going pretty smoothly.

Then I got to the part where U4 (50 MHz oscillator) is installed. After reading Dave’s (AA7EE) note about solder bridging the pad and cap of U4, I was trying to avoid doing the same thing and in the process ended up bridging the pad and cap anyway. Argh.

After some application of solder wick followed by wailing and gnashing of teeth, there was one pad that still seemed to be bridged that I couldn’t fix.

Dave helpfully pointed out that one of the pads Is GND, which just happened to be the pad I thought I was having an issue with. So with any luck, U4 hasn’t been cooked by me trying to wick away solder that wasn’t causing a problem anyway (just in case, Jason is also sending another U4) and I can continue on.

Next step is to install U5 (DDS chip) with teeny tiny leads.

It took me about a little over an hour and some fumbling around with Very Small Pieces, but the power conditioning part of the CC1 transciever is done.

There it is in the lower left corner. 2 very small transistors and some small capacitors and resistors.

Applying 12V power gives me a good voltage at the 5 V test point, but nothing at the 3.3 V test point. I think I may have either cooked the transistor or there’s a solder bridge I can’t see. I’ll have to take it off and check underneath.

Things I’ve learned so far:

• Keep the board flat. I had one of the transistors bounce off the board and go sliding off onto the floor when I took it out of the packaging. Took me 10  minutes of hunting on my hands and knees to find it.
• I initially started with a pointed tip on the soldering iron, but found that the chisel tip seems to work better. The flat surface of the chisel tip allows you to put more heat on the component and pad than the pointed tip.
• A magnifying light is pretty much essential for this.
• Use 0.55 mm or thinner solder
• Tack one end of the component to the board with a small amount of solder. Then you can solder down the other side or other leads pretty quickly and easily.
• Go ahead and solder the barrel connector (J8) to the board. This will make supplying power for testing easier.

I’m only doing one component at a time, so it’s probably going to take me a while to finish.