Equipamento: Dell OptiPlex 3020

Problema: Não liga (Sem sinal de partida)

Detalhes do Diagnóstico:

Comportamento da Fonte: Ao conectar o cabo de força, o LED traseiro da fonte permanece apagado. No entanto, ao pressionar o botão de auto-teste (BIST) na traseira, o LED verde acende e os coolers (da fonte e do processador) giram, mas param assim que o botão é solto.

Painel Frontal: O computador não responde ao botão de ligar original.

Teste de Jumper: Foi feita a tentativa de ligar a placa-mãe diretamente através dos pinos do painel frontal com chave de fenda (jumper), mas a placa não deu partida.

Estado Geral: Não há sinais de componentes visualmente queimados ou capacitores estufados.

English: Why doesn't my Dell 3020 give any sign of life?

Equipment: Dell OptiPlex 3020

Problem: Does not turn on (No start signal)

Diagnostic Details:

Source Behavior: When connecting the power cable, the rear LED of the source remains off. However, when you press the self-test button (BIST) on the back, the green LED lights up and the coolers (from the source and processor) rotate, but stop as soon as the button is released.

Front Panel: The computer does not respond to the original power button.

Jumper Test: An attempt was made to connect the motherboard directly through the front panel pins with a screwdriver (jumper), but the board did not start.

General Condition: There are no signs of visually burned components or stewed capacitors.

⟐ Edited abril 29, 2026 at 5:46 GMT-7

Here is what I've tested:

• The issue occurs in both Windows 10 and Linux Mint Cinnamon.
• I tried two different 3.5 mm microphones, and both have the same problem.
• The front and rear microphone jacks both produce the same buzzing.
• I reseated the front panel HD Audio connector on the motherboard.
• The motherboard uses a Realtek ALC3220 audio codec.
• The microphone buzz is present in all recording applications.

What could have failed on the motherboard that would cause this? Could the PSU replacement have damaged the onboard audio circuit, or is there another likely cause? Are there any tests I can perform with a multimeter to determine whether the problem is the motherboard, front panel audio board, grounding, or something else?

Any troubleshooting suggestions would be appreciated.

Please help me i really need mic