Symptoms:
A single maximizer will be 'stuck' — not running (sometimes reported as brownout or low voltage).
In Grafana you'll see it isn't detecting ripple.
The device is wired correctly (output current matches others in the string) but has an output voltage near zero.
This often happens with maximizers near the 'middle' of a string.
Why it happens:
Each maximizer detects it is OK to run by measuring 'ripple' on the DC bus. Maximizers can only measure ripple proportional to how 'far' they are from the ground reference. A maximizer so 'close' to ground may not see enough ripple to activate.
A broken or miswired ground can also cause maximizers to not operate.
Troubleshooting Steps:
Reset a single maximizer at the 'end' of the string — ideally the one on the same side as the ground ref voltage.
Pick the maximizer at the 'bottom' (most negative ground ref voltage) if the non-working maximizer's ground ref voltage is negative.
Pick the maximizer at the 'top' (most positive ground ref voltage) if the voltage is positive.
Resetting that end maximizer temporarily increases the proportional ripple seen by all other maximizers. This should push the stuck maximizer over the threshold to start operating. Once it starts, it uses a different (lower) threshold to stay running.