Ren-W Troubleshooting

The Ren-W circuit board is a very simple design but good soldering technique is still extremely important.

Voltage Measurements: three test points are just below pin 16 of the MAX232 chip/socket:

• Be certain that the following components are mounted on the board properly:

• The notch on the MAX232 chip faces to the right, toward the U1 voltage regulator.
• The zener diode (D1) has the black stripe on the TOP, next to the JP6 header pins.
• The 3.3 voltage regulator (U1) has the metal tab facing up, toward the JP2 header pins.
• The electrolytic capacitor (C3) has the - stripe facing DOWN toward the LED, which means the + side is up toward the J2 jack.
• The LED (D2) while not shown in this photo, has the cathode (flat side) facing the mounting hole to its right.
• Resistor R1 (33 ohms) is immediately below the MAX232 chip. The resistor has no polarity concerns.
• Resistor R2 (1k ohms) is immediately to the left of the LED. The resistor has no polarity concerns.

• When you study the underside (copper) side of the circuit board, a few things become readily apparent:

• Very few pins of the XBee radio modules are actually used; most are unused and serve only to hold the header pins securely.
• The solder pads for the XBee headers are very small; accurate and careful soldering is a must to prevent solder bridges. A solder bridge could prevent the XBee radio from functioning properly.