PC only turns on after pressing the power button several times

Troubleshooting Persistent Power-On Issues on an HP ProDesk 600 G2 SFF

Understanding and resolving power-on problems in desktop computers can be both challenging and frustrating. If your HP ProDesk 600 G2 Small Form Factor (SFF) PC exhibits behavior where it requires multiple attempts to fully power on, you’re not alone. In this article, we’ll delve into a common scenario, analyze potential causes, and provide actionable solutions to help restore normal startup functionality.

Scenario Overview

A user reports that their HP ProDesk 600 G2 SFF, equipped with an Intel Core i5-6500 processor, 8 GB DDR4 RAM, and a 250 GB SSD, experiences a peculiar startup issue:

• Initial power button press results in the keyboard lighting activating, but the mouse remains unlit, and there is no display output.
• Pressing the power button again shuts down the system.
• Repeating this process approximately three to four times eventually boots the computer normally, at which point both keyboard and mouse lights turn on, and the system operates without issues thereafter.

This pattern suggests inconsistent power-up behavior, which can stem from various hardware or BIOS-related causes.

Potential Causes

1. Power Supply Anomalies

An insufficient or failing power supply (PSU) may deliver inconsistent power, leading to startup quirks. Although SFF systems are generally reliable, aging PSUs or those not adequately rated for internal components can cause similar symptoms.

1. Motherboard or BIOS Issues

Firmware problems or outdated BIOS versions can impair initial startup sequences, especially when hardware initialization is inconsistent. This often manifests as delayed or repeated power attempts.

1. Peripheral or External Device Interference

Sometimes, peripherals connected to the system can interfere with the boot process. This is especially true if external devices draw power or send signals during startup.

1. Hardware Seating and Compatibility

Improperly seated RAM modules, loose connections, or hardware conflicts can cause failed initial power-ups, requiring multiple attempts to get the system to POST successfully.

1. Power Button or Front Panel Connection

Faulty wiring or a defective power button switch can lead to inconsistent signals to the motherboard, resulting in the need for multiple presses.

Recommended Troubleshooting Steps

1. Perform Basic Hardware Checks

2. Ensure all internal components, especially RAM modules, are properly seated.

3. Check all power supply cables and connections, including the main motherboard connector and the power switch cable.

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