Carolina Flashers
Photonics Group
| Welcome to the Carolina Flashers Photonics Group |
The instruction manual for the LB56C uses the venerable “checklist” style of guiding you through the construction process. First, there’s a checklist of all the components, and then there’s another checklist which has you insert and solder the components onto the PC board. If you’ve never built a kit before, you’ll probably be best served by following these instructions to the letter. However, the manual itself admits that you can just as well insert the components in any order, so we chose to pretty much combine verifying that we’d received the components with actually stuffing them into the board. |
We did mount and solder the two jacks, the on/off switch, and potentiometer R14 (the “volume control”) first, not for any good reason. Doing so just seemed satisfying to us. Next, we installed the resistors. One great thing about modern kitbuilding is that all the components are supplied to the companies which produce the kits in rolls for use in automatic component insertion machines. For example, all six of the 1KΩ resistors are connected together, which makes inventorying a snap, and while you have them in hand, you can go ahead and stuff them into the PC board. The parts list on page 6 tells you the schematic symbol numbers, and the pictorial diagram of the PC board shows you where those numbers are located. Time is saved because you only have to handle the parts once instead of twice. We put in all the resistors first, soldering each one and then trimming off the excess component leads immediately afterward. (Save three or four of the clipped off resistor leads, because you will need them later.) These “fixed value” resistors are non-polarized components, meaning that they can be installed either way, but we generally like to install them so that the first color that indicates the resistor’s value is oriented to the left when you’re reading the component number on the PC board. It’s just a thing with us! The old carpenter’s adage of measuring twice and cutting once is worthwhile here: removing a component after it’s been soldered and trimmed is a pain, so take care to make sure each one goes where it should. There are two other resistors which get soldered to the board: potentiometers R2 and R4. Once you’ve finished installing the resistors, you’re almost halfway through! |
After the resistors have all been installed, the transistors and diodes might be good to do next. Unlike the resistors, these are polarized components, which means they can only be correctly installed one way, so make extra sure you’ve done these correctly before you solder them. Let’s do the transistors first. There are nine transistors, all identical, and they’re labelled Q1 through Q10. Wait a minute! How can nine transistors fill ten slots? Easy, because for some perverse reason, there is no Q9 on the PC board, just Q1 through Q8, and Q10. Why? Who knows? Anyway, if you observe the orientation of the flat spots on the board and install the transistors accordingly, you cannot go wrong! Next, install the photodiode, D4 (with the bump facing away from the board), and then the LED, D1. You'll notice that the board allows you to install D1 in two ways, and the correct way for you is with the small bump facing out, like D4, and with the longer of the two leads (the anode) in the center hole (see Instruction #34 on page 11 for a clarification on this). The detector diode, D3 is made of glass and is the most fragile component in the entire kit, so be careful bending the leads on it. Make sure you observe polarity with this one, also. |
Now let’s do the capacitors. There are two kinds: the disc capacitors, which are not polarized; and the electrolytic capacitors, which are. Install the three different values of disc capacitors first, and then install the two values of electrolytics. We’ve never really understood why most circuit boards have the polarization of ’lytics marked with a plus sign, but the ’lytics themselves usually have the minus terminal marked, but, needless to say, the negative terminal of the capacitor should not go into the PC board hole marked positive. We hope we’ve made that clear. |
It was at about this point in our assembly work that we noticed something curious: The volume control (R14), part of the receiver, was on the circuit board that was labelled as “LB-5 TRANSMITTER.” J1, the headphone jack, was also on the “transmitter” board, and J2, the microphone jack, was on the “receiver.” For a moment, we thought our old childhood dyslexia had returned, so we stopped for a minute to conduct a reality check. That’s when we discovered that the silkscreened markings for “LB-5 TRANSMITTER” and “LB-6 RECEIVER” had been inadvertantly reversed when the PC boards were made. It took a little while for this to sink in, because you do not normally find a mistake of such magnitude, especially on a kit which has been in production as long as this one has. But a cross-check between the PC board itself and the pictorial of the PC board on page 7 of the manual made the discrepancy plain. We took this in stride after figuring it out, but it could be a real show-stopper to a first-time kit builder. We sure hope Ramsey fixes this! |
Remember those clipped off resistor leads you were saving? Use them to form jumpers going from board to board at JMP1 and JMP2. Another jumper goes in at JMP3. Solder the wires from the battery connector to the appropriate (black to minus, red to plus) holes between S1 and J2. Install the battery clip next. We think it would be good to affix it to the PC board with a small piece of double-sided MACtac tape instead of the wire and solder arrangement that Ramsey suggests, but that’s your call. |
We saved installing U1, the integrated circuit, for last because it’s the component whose leads are closest together and most likely to be bridged with solder. You now have much experience with your soldering iron and the characteristics of this PC board and should therefore have no trouble with it. |
And now...you’re done stuffing the PC board! Wasn’t that fun? We are fully convinced that a person can become addicted to the aroma of rosin flux. It’s the smell of creation taking place! You have taken a pile of lifeless components and transformed them into a device that will both respond to and modify its environment--almost a living thing! Take a deep breath, have some coffee and check the solder side of the board one last time to look for any errant solder. Use the hardware provided to mount the PC board within its case through the front panel, install the knobs and the back panel (red plastic--we had to trim ours with scissors to make it fit). Get yourself a nice, fresh 9V battery. Make sure S1 is in the “off” position (the little white plastic piece in front is sticking out at its farthest). Connect the battery to the connector and insert the battery into its holder. Set the top of the case onto the bottom. (We'll screw them together later.) Stick the little feet onto the bottom of the case and stand back and behold your handiwork. |
Now let’s test this puppy! (Don’t forget to unplug the soldering iron.) |
