Dell T3600 turns on sometimes and sometimes it doesn't showing an amber light with the numbers 134.

Hi

Quite a mixed bag...

Symptoms and likely cause

An amber power LED plus amber blink pattern 1‑3‑4 on Dell Precision T3600 commonly points to a PSU or power‑rail/cable failure or an early power‑good problem on the system board.

Intermittent boot (sometimes powers on, sometimes amber 134) usually means the fault is marginal: a failing PSU or a poor connector, or a failing board/component that only fails under certain conditions.

Step‑by‑step troubleshooting (in order)

1. Basic isolation (no tools beyond static care)

Disconnect AC, press and hold power button 15–30 seconds to drain residual charge, reconnect AC and test.

Remove all external peripherals (USB, network, drives, front panel cables not required for POST) and try power on.

2. Check PSU and PD (power distribution) connections

With unit unplugged, open case and visually inspect the PSU, PD board, and large 24/8/4‑pin motherboard connectors for loose pins, burn marks, or swollen capacitors.

Reseat every PSU cable to the motherboard and to the PD board; unplug and replug them firmly. Test again.

If you have a known good compatible T3600 PSU (or spare working T3600 unit), swap it in — T3600 uses specific PD board/PSU pairings, so use the exact Dell T3600 PSU model when testing.

3. Test minimal configuration

Remove all expansion cards (GPU, RAID cards, etc.).

Remove all but one RAM module; try each module in each recommended slot one at a time to rule out bad DIMMs or slots.Try booting with only CPU, one stick RAM, and onboard video (if present) to see if amber 134 persists.

4. CMOS/BIOS reset and battery

Remove the CMOS battery for 5–10 minutes (or use the CMOS clear jumper) to clear NVRAM; reinstall and test.

If battery is old (several years), replace it — a failing CMOS battery can cause erratic POST behavior.

5. Inspect GPU and motherboard components

If swapping the PSU and isolating RAM doesn’t help, inspect the GPU (if fitted) for visible damage; test with known good GPU or use onboard video if available.

Check motherboard for blown capacitors, burn marks or bad solder joints around power circuitry.

6. Diagnostics and service options

If the board posts intermittently, run Dell diagnostics if you can reach POST or use an external POST card/beeper for beep codes when possible.

If you confirm PSU swap fixes it, replace PSU with a correct Dell T3600 part (match wattage and PD board compatibility).

If problems remain after PSU replacement and cable reseat, likely cause is failing power distribution board or motherboard — these often require replacement.