Why does my PP III make a crackling sound

through the speaker as I connect it to my circuit?

What you are hearing is the probe tip puncturing through the corrosion or oxidation layer as you are connecting it to your circuit. You can simulate this by dragging the probe tip across the positive of a battery terminal (Turn the speaker tone off for a better effect) Take notice that while you hear the crackling from the speaker you will also see a “P” Icon in the lower left hand portion of the LCD. What is going on here is Mode 1 not only has the ability to display DC voltages but also AC voltages. What makes this function unique is that you as a user can set the threshold level (Mode 5) and the display will switch from displaying DC to AC voltages. Not only do you get the reading of the Peak to Peak AC voltage but you actually get to hear that AC voltage... the Crackling Sound!

This audible feature enables you to:

• Hear bad connections due to oxidation or corrosion and also allows you to listen for poor

  connections as you wiggle wires.

• Quickly find malfunctions due to high ripple from bad diodes in the alternator. (You actually

  hear the alternator whine as you rev the engine)

• Verify and trace various audio sources from Stereo Pre- Amps and Power Amps.

• Listen to logic circuits from the Engine Control Unit (ECU, ECM) for activity.

The voltage threshold level setting can be manually adjusted to

7 different levels:  0.2v, 0.5v, 1v, 2v, 5v, 10v, and 50v.

If you would like to adjust the threshold level setting higher, hold down the mode button for an extended push until you hear a beep. Repeat this step 3 more times until you see 1.0 on the display.  Each subsequent quick press of the mode button will increase the preset voltage level setting. The settings loop from 0.2, to 0.5, to 1.0, to 2.0 to 5.0, to 10.0 and to 50.0.  Once you reach your desired threshold level setting, hold down the mode button again for an extended push until you hear a beep and you will be back in Power Probe Mode and ready to use your Power Probe.   Each time you re-connect your PP III to the vehicle’s battery the setting will default back to the last known setting. You can also download this handy chart:  PP3Navtree_v3.pdf

What is Audible Monitoring (Quick Answer)

Let’s you hear the signals of a circuit through the Power Probe III speaker.

What is Peak to Peak? (Quick Answer)

Another term is MIN/MAX or MAX/MIN. Maximum peak voltage minus the minimum peak voltage shown on the Power Probe III display.

What is “Voltage Level Threshold Setting?”

The Voltage Level Threshold Setting is just that. It is a setting. This setting is adjusted by holding the oval mode button down for 2 seconds and repeat that a total of 4 times, until the display shows an alternating plus, minus, sign in the lower left hand corner.

When that happens, you can then quick tap the mode button to set the threshold level from 0.2 volts to 50 volts. Once you have the desired voltage level on the display, hold the mode button for 2 seconds until you hear the Power Probe III Mode tone (that is the same tone you hear when you first connect the Power Probe III to a battery). When you hear that tone, then you have succeeded in returning your unit to Power Probe Mode with the voltage level threshold set to that value.

What is Audible Monitoring and Peak to Peak measurement?

It is sort of like having an audible oscilloscope. You can hear the circuit signals as they pulse and whine, along with seeing the MAX/MIN reading on the display.

When you probe a circuit that has an AC signal or a pulsing signal or even an audio output that exceeds the voltage level threshold setting, the Power Probe III will audibly reflect the signal through its speaker.

1. If you are probing a circuit while the engine is running, and the alternator ripple exceeds the threshold setting, you will hear the speaker whine as you accelerate and the display shows the peak to peak measurement.

2. If you are probing a distributor pickup that you are holding in your hand, you can spin the shaft and hear the clicking of the pickup to verify if it works.

3. If you are probing a fuel injector while the engine is running you will hear the pulsing signal that feeds the injector and the display shows the peak to peak measurement.

4. If you connect to the output of a car stereo and the volume of the signal exceeds the voltage threshold setting, you can hear the music or whatever is playing at the time.

5. If you connect to the circuit that has the open circuit tracer signal on it, you will hear the 4 kHz tone. As the Audible Monitoring is happening, the Power Probe III shows the peak to peak measurement on the display.

How fast is the Peak to Peak feature?

It measures 4 times per second.