This troubleshooting tip is specific to DiveCAN systems.
There are several possible root causes for a peripheral unit (Petrel, Nerd, LED HUD) that turns on by itself or cannot be turned off. These include damaged head electronics, an issue with the cables or connectors, or a problem within the peripheral unit itself. The first step to troubleshooting is to isolate whether the issue originates from the unit itself or from the head electronics as outlined in Tip #1.
For dual DiveCAN systems, temporarily connect the unit to the other available port. For example, if a controller won’t turn off, try plugging it into the monitor port and observe its behavior. Keep in mind that swapping ports may cause the display to show an error message. Alternatively, test the peripheral in a different rebreather head to determine if the problem persists. Peripherals that are self-powered (such as Petrels and Nerds) and can be unplugged from the rebreather head are the easiest to troubleshoot. If these units can be turned off when disconnected from the rebreather, it indicates there may be a problem with the rebreather head. These units may also display error messages such as “Bus Turnoff Fail”, that can help to identify the source of the issue.
If a non-self-powered LED HUD keeps turning on, first check whether its button is stuck. Sediment buildup, corrosion, or moisture inside the unit can cause the button to stick or malfunction. If the button appears fine, proceed as in Tip #1 by isolating the issue - try different head electronics with the same HUD or test a different HUD on the same head.
Another potential cause is firmware behavior. Specifically, the unit remains active because it detects activity from a wet contact or pressure sensor. Depending on the model, resolving this may be as simple as drying the wet contacts. Avoid using high pressure air to dry any dive computers as that could easily damage sensitive components. Note that Petrel 3 models use the titanium buttons as wet contacts; certain metallic protective covers can interfere if they are in direct contact with the buttons.
If the pressure sensor incorrectly indicates that the unit is underwater, it might prevent shutting down or changing some settings, like switching to the 0.19 storage setpoint on controllers. Indications of a faulty pressure sensor include depth readings when at the surface, “ERR” replacing depth, or fluctuating depth readings between some value and zero. Unfortunately, if the pressure sensor is faulty, there’s little that can be done in the field and the unit should be sent to an authorized service center for investigation.
Following these tips will help isolate the source of the issue so you can get back in the water as quickly as possible.
