why does my canon pixma tr8620a use so much power? i can hear it humming even when it's 'off'.

Diagnosis

The humming sound you hear from your Canon PIXMA TR8620a is caused by "coil whine" or electromagnetic vibration emanating from the internal switch-mode power supply (SMPS). Even when the printer appears to be "off" via the power button, the device is actually in a low-power standby state. In this state, the internal circuitry remains energized to maintain the wireless network connection (Wi-Fi), keep the print head primed to prevent ink clogging, and monitor for incoming fax signals or remote wake-up commands from your computer or smartphone.

This specific model is designed with an "Auto Power On" feature and a constant network listener. The hum is the result of the transformer within the power board vibrating at a frequency audible to the human ear, which is exacerbated if the printer is placed on a hard, resonant surface like a wooden desk. You can confirm this is a standby issue by observing the power button; if it is glowing amber or if the display panel wakes up instantly without a boot sequence, the motherboard is still drawing current and the power supply is active.

How to Fix It

To eliminate the hum and stop the phantom power draw, you must bypass the software-level "Off" switch and cut the physical electrical circuit. Follow these steps for a complete shutdown:

1. Press the Power button on the top control panel and wait for the screen to go completely black.
2. Locate the AC power cord at the rear of the printer. Grip the plug firmly and pull it directly out of the wall outlet or the power strip.
3. If you are using a surge protector, flip the master switch to the OFF position.
4. To prevent this from happening daily, plug the TR8620a into a power strip with an integrated on/off toggle switch. This allows you to kill the power to the SMPS without repeatedly unplugging the cable, which prevents wear and tear on the printer's power socket.
5. When you are ready to print again, flip the switch on the power strip back to ON and press the printer's power button to initiate the full boot-up and cleaning cycle.

If That Didn't Work

• Disable Auto Power On: Navigate to the Setup menu on the LCD screen, select Device Settings, then Energy Saving. Turn off the "Auto Power On" feature. This reduces the frequency with which the printer wakes itself up, though it may not entirely silence the SMPS hum if the plug remains in the wall.
• Change the Surface Material: If the hum is loud, it is often amplified by the furniture. Place a thick rubber anti-vibration mat or a neoprene pad (roughly 5mm to 10mm thick) underneath the printer. This decouples the vibrating power supply from the desk and significantly reduces the audible noise.
• Check for Firmware Updates: Access the Maintenance menu and select Firmware Update. Occasionally, Canon releases updates that optimize the power management profiles of the motherboard, which can reduce the voltage draw during standby and potentially quiet the coil whine.
• Isolate the Power Source: If you hear a buzzing sound coming from the wall rather than the printer, you may have "dirty" power or electrical interference on that circuit. Plug the printer into a different outlet on a separate circuit breaker to see if the humming persists.

Heads Up

• Ink Maintenance: Be aware that cutting power completely via a switch or plug means the printer cannot perform its automatic "mini-cleans." If you leave the printer unplugged for more than two weeks, you may experience clogged nozzles in the print head, requiring a costly "Deep Cleaning" cycle.
• Power Surges: Always use a surge protector. The TR8620a's power board is sensitive to voltage spikes; a sudden surge during a thunderstorm can fry the SMPS, turning a quiet hum into a permanent failure.
• Avoid "Hard" Resets: Never pull the power plug while the printer is actively printing or performing a head cleaning cycle, as this can lead to mechanical jams or corrupted internal memory.