ThunderBell Module Kit Instructions
Page 4 of 8
Chip Sockets (±)
There are two 8-pin sockets. Sockets are marked with a small notch on one end that must line up with the notch in
the PCB outline. Once the socket is soldered in place, the PCB outline will not be visible, so it is important that the
socket is oriented correctly in order to ensure that the chip is oriented correctly when it is inserted into the socket.
Electrolytic Capacitors (±)
Electrolytic capacitors look like little tin cans with two wires sticking out of the bottom. The value is clearly printed on
the capacitor. Both electrolytic capacitors in this kit are the same value (10 µF).
Electrolytic capacitors are polarized, so it is important that the right lead goes in the right hole. The negative lead on
the capacitor is the shorter one and it is marked with a gray stripe on its body. The positive lead is longer. The
positive hole on the PCB has a square pad and is marked with a plus sign.
Voltage Regulator (±)
There is one voltage regulator chip in the kit. The voltage regulator has the same basic shape as a transistor. There
are several ways to tell them apart. First and foremost, the voltage regulator is marked with the part number 78L05.
Second, the voltage regulator is loose and the three transistors are taped together. When in doubt, read the marking
on the part.
The voltage
regulator’s PCB outline is labeled REG1. The outline is similar to that of a transistor, so make sure you
put the regulator in the right place. Make sure that the flat side of the voltage regulator lines up with the flat side of the
outline on the PCB. The regulator will not sit flush against the PCB. Do not force it down any further than it will go with
a gentle pressure.
The regulator is more heat sensitive than most of the parts in this kit, so take care not to let the soldering iron linger
too long. If you are unsure, then solder one lead at a time and let the part fully cool off before soldering the next lead.
Transistors (±)
There are four 2N3904 transistors in the kit. The transistor PCB outlines are labeled Q1 through Q4. The outline is
similar to that of the voltage regulator, so make sure you put everything in the right place. Make sure that the flat side
of the transistor lines up with the flat side of the outline on the PCB. The transistors will not sit flush against the PCB.
Do not force them down any further than they will go with a gentle pressure.
Transistors are more heat sensitive than most of the parts in this kit, so take care not to let the soldering iron linger
too long. If you are unsure, then solder one lead at a time and let the part fully cool off before soldering the next lead.
