Yes, especially if I had a schematic for them. Lacking a schematic it seemed prudent to ask here if others had the same issue so I didn't have to spend a week tracing printed circuit paths.
All LEDs losing brightness in the same time could be indication of voltage regulator failure. There are control points on the PCB, but without electronic diagram and specifications it will be a bit challenging to find what's wrong. I would check the following:
- power supply voltage first, must be 19V under load.
- visual inspection of the PCB, any damage signs or something that doesn't look normal, oxidation around voltage regulators.
- if the LEDs are anode or cathode driven. There is a resistor in series to each LED, could be on the anode or cathode side. One side of the LEDs must be connected to the GND or to VCC. It's easy to find which one it is.
- measure LED voltage at LEDs. An oscilloscope is needed for blinking LEDs or a digital AV meter with memory. Simple AV meter won't work on a fast switching circuit (blue LEDs need >3.2V to light up). Check the Power LED voltage, it must be on constantly.
- if voltage at LEDs is too low, find which voltage regulator is responsible for LED's and look closely at this particular one.
Can't find ASUS repair information anywhere. Top secret products, I guess. With a bit of service information it would be a quick fix. I'm an electronic engineer, used to repair computer PCBs on a component level in the past. I can reverse engineer the router's hardware, but it's not worth the time and efforts. 2h time spend on this already exceeds the unit cost.