Monitor damage from improper cable connection and power configuration on camera rig

Gear

ZephyrCan I fly my Alexa or RED on a Zephyr?389

Master SeriesIs a used Master Series rig worth buying as a first big rig?191

BFDHow do I power my BFD receiver from my camera or sled?186

VoltCan I retrofit a Volt onto my existing sled or gimbal?168

ArtemisHow do I power my camera and accessories from an Artemis sled?166

MDRWhere can I mount my Preston MDR on my rig?143

ModulusIs there a Modulus option for HD wireless video?141

G-70Will my G-70 fit my vest, gimbal or sled?126

FI+ZCan I control iris and zoom wirelessly, not just focus?60

HU3Where can I get my HU3 repaired, refurbished or repainted?60

CineLiveHow do I pack and case my CineLive rig for transport?54

G-70XHow does the G-70X compare to Pro Titan, Xarm and other arms?46

Trinity 2Is Trinity 2 SUP 3.0 firmware safe to install or buggy?46

Ultra VestWhich vest should I choose for my body size, comfort and operator type?39

2014Batteries/Power forum

12 years old. Gear and prices may have changed since.

DisputedParticipants disagreed and reached no conclusion. Read the findings as positions, not as an answer.

Connecting a monitor cable to a powered-on rig can cause voltage to travel through signal paths instead of intended power paths, damaging the monitor's circuitry.
Marshall monitors with single internal ground lines for both power and signal transmission are vulnerable to damage when power is connected before ground during cable attachment.
Operating a rig in 24-volt mode while a monitor is connected via a multi-pin cable can deliver excessive voltage to monitor components not designed for it.
Some monitor models have standby buttons that keep the device powered even when appearing off, allowing damage to occur from overvoltage despite the power switch position.
Damage to monitor SDI circuit boards can occur from ground loops created when multiple battery sources power different components on the same sled.
All power should be disconnected before making cable connections to prevent ground loop formation and accidental voltage reversal.

The exact cause remained uncertain even after investigation, with multiple theories proposed including 24-volt mode operation, connector contact sequence, and ground loop formation.
The discussion conflates different potential failure modes without definitive resolution of which mechanism actually caused the damage in this specific case.
Repair costs and availability vary by location and monitor model, with some users reporting recurring failures on the same monitor type.
No consensus reached on whether the issue is specific to Marshall monitors or affects other brands like Transvideo.