The cooling fans in the main cabinet are usually the size of a computer fan and spin at 10,000 RPM. They fail silently. When they fail, the board cooks itself.
If your manual’s troubleshooting flowchart leads you to "Check AC input," and that’s fine, immediately suspect C1, C2, and C5 on the PSU. 3. Fans, Filters, and Heat (The Silent Killers) The FANUC 15M manual dedicates an entire chart to environmental specs. It wants to be between 0°C and 45°C (32°F to 113°F). But here is the reality: fanuc 15m maintenance manual
Change batteries with the power ON. (Yes, on. Static discharge is a killer). Pro Tip: The manual specifies 3V Lithium (BR-2/3A or equivalent). Buy a 5-year supply. Change them every New Year’s Day, regardless of voltage. 2. The "Yellow Cap" Capacitor Plague Flip to the section on the Power Supply Unit (PSU) . The manual has a nice diagram of the board. Look at the large electrolytic capacitors. The cooling fans in the main cabinet are
Over 30 years, the electrolyte dries out. You will eventually turn on the machine and see a blank screen or a "System Error." The manual will tell you to check input voltage. But the veteran knows: Recap the power supply. If your manual’s troubleshooting flowchart leads you to