I have a dead Logitech Z-680 5.1 computer speaker system that I was wondering about doing salvage work on, before discarding.
It consists of a subwoofer with all the amp circuitry and connectors for the main speakers on the back, and a dedicated control pod that connects to it using a custom wired DB9 connector.
The system stopped working and, since it was under warranty (and discontinued), Logitech simply replaced the entire thing with the current model (Z-5500) and does not want any of the old equipment returned. The old and new systems are electrically incompatible, so I just boxed the Z-680 setup and am triyng to decide what to do with it.
The electronics pod, which contains the controls, analog/digital inputs, Dolby/dts decoders, and preamp, powers up and detects and processes input signals appropriately. There is a power-on "thump" in all speakers when you fire the thing up, and the sobwoofer still has a little buzz coming out of it (that was normal), but after that ... nothing. Audio goes in, but not out. There is a special test mode that sends tones to all speakers for setting levels ... I hear nothing.
I'm not sure if the failure is in the pod or the main (audio) unit on the subwoofer, though I suspect the former. I opened the pod ... lots of surface mount chips, no visible fuses or resettable devices. Not user-serviceable.
The subwoofer has this huge metal cage bolted on the back which contains the audio amplifier circuits. I'm pretty sure the DB9 input on the back contains the 6-channel preamp output from the control pod. I was thinking of trying to send some test signals into the subwoofer's input socket, 2 pins at a time, until I figure out whether any of them elicit audio output from the speakers. Perhaps I can salvage the subwoofer and simply hook a line-level audio cable to whichever of the two DB-9 pins gives the desired effect.
Comments/suggestions? Thanks.