Check measurement points

Check all voltage measurement points. Do not check the current one, because for measuring a current you have to break the circuit. Measurement points are those small tables in the schematics with various variables. Check the values in Receiver an Nebulus transmitter. Determine if the measured voltages are in the specified range. The voltages are measured against ground (i. e. the tin of the can). The values should be all OK. If they are not, perform once more correctness check of the affected module. If the problem persists after that, ask on the mailing list.

Testing RSSI operation

Check whether the TX diode shines using a digital camera. Connect 200mV voltmeter into Receiver's RX level DC measurement (Received Signal Strength Indicator, RSSI). Check whether the multimeter readout reacts to the light strength from the transmitter.

Preemphasis setting

• Do preemphasis test of Inferno.
• Change value of R9 according to the result:

  Result	Action
  LED shines too long	Increase R9
  LED shines too short	Decrease R9
  OK	Done

Performance Measurements

Do at least one from the following Inferno tests (if you don't have prerequisites for one, then go to another etc.):

• NED measurement
• BER measurement
• Packetloss measurement

If something is wrong

If you are getting substantially smaller ranges (for example 0.7m for SFH203), something is wrong.

The input transistor of the receiver (Q101, BF908 or its equivalent) can be broken-through. It is caused by inappropriate handling: the device is static electricity sensitive. It can be caused also by soldering with an iron with ungrounded tip or transformer soldering gun can generate spikes during switching. This sometimes manifests as a voltage greater than 0V on P103. My healthy receiver has 0.1mV on P103.

A breakthrough of G2 sometimes manifests itself as a receiver that is oscillating (doesn't work at all or has inferior range) where the oscillations cease when C103 is removed from the circuit.

Breakthrough of Q101 can be fixed only by replacing with another one and obeying the rules for manipulation with static electricity sensitive devices.

Range reduction

If you plan to use Ronja on a link less than 1/4 of nominal distance, then perform range reduction now.