Logitech Z-5500 Schematic Diagram -

Once you have a diagram (even a partial one), here is how to revive your Z-5500.

Satellite speakers work, but the sub is quiet or hums. What the schematic tells you: The subwoofer channel has its own discrete amplifier circuit with large rail capacitors (often 35v 4700uF). The Fix: Check the schematic for the "Sub Pre-amp" section. Replace the TL074 or JRC4558 op-amp. Also, inspect the 5W cement resistors—they crack open frequently. logitech z-5500 schematic diagram

The power supply board generates several critical rails, including ±18V for the op-amps and +8V for the control circuitry. Once you have a diagram (even a partial