Logitech Z680 left front channel problem

wookieloou

Member
2010-12-10 4:27 pm
Howdy everyone, first time poster to these forums. I have been scouring the web and finally found a place where people are actually trying to FIX things instead of just throw more money at replacing the entire system.

I'm relatively novice to Audio but have a background in computers and electronics and have been able to fix my own issues for many years. I am in no way an electrician or engineer so if I'm not wording things correctly I apologize in advance.

I have a Logitech Z680 that I was mounting in a theater room for surround sound (was only using 2 front satellite speakers and center channel for probably 6 years with this unit) and during the process left all audio coming out of the left front channel. During the install I was hot swapping speaker cables while the speakers were running to tone out some speaker outlets in the wall that go out to different walls and places in the room, which of course were not labeled. As I was finishing the last pair I went back to test the speakers all at once and noticed I was getting no audio from the left front channel, where I was several minutes before...

The troubleshooter in me immediately checked the wiring up to the satellite speaker, everything tested good. Tried another satellite speaker on that channel and still no good. Frustrated I made sure that the clamps on the back of the amp were making contact with the wire and all seemed to physically be conducting at that level. I guess I could have taken it a step further and run a multimeter on that channel to see if anything is even coming out.

As this speaker system is out of production and waay out of warranty I was determined to fix this myself. I opened up the amp casing and tried to look around for any blown capacitors or contact points that might have come loose to the circuit board. I did blow out a ton of dust and got a decent look at things but it appears I'm going to really have to take this thing apart to be able to figure out what's failed.

What starting points do you gentlemen recommend?
Should I start by verifying the integrity of the capacitors?
Is it a transformer that is possibly blown for each channel?
Can I take any pictures or find the model number of the type of amp to give you guys a better deal of what I'm working with inside?

I'm a pretty proficient googler and wasn't able to find much information on the specific components inside the amp/sub unit. Any help or direction is appreciated, let me know if anyone thinks this is salvageable without having to take this into a shop and getting charged up the ying.