Head unit developed problem

[Super mud]

Well I finnaly fixed all the important stuff on my xj and just recently had the time to throw in a head unit since the original owner wanted his. (He left some nice speakers so I was psyched to see how it sounded. Also my friend found 2 head unit just laying in his garage just out of nowhere so perfect timing. I grabbed the pioneer and wired that sucker up, ordered a weird ipod adaptor for it and was rockin for a week staright till it started screwing up. I thought u got to be kidding me, I would like to at least do one thing to my jeep which I don't have to mess with or fix more than once. So what happened is the stereo would start acting up every few minutes and gradually got more often. It would have static like skips in the sounds. So the next day i turn it on and the I get no sound at all except when I switch between radio, cd and stuff the speakers pop a little because of the system change or whatever. Now the head unit it self works fine, no power loss or anything but the speakers are just not producing sound. I thought it could be a ground problem but I'm not familiar with audio electronics. Don't the speaker grounds run back to the head unit? and the head unit itself is grounded.
I was going to probe the power feed wires to the speakers to see if they are getting voltage from the head unit also just been working on other stuff so I thought I'd see if anyone had any idea what the problem could be before I waste a day on one thing.

 

[Talyn]

How do you know that the head unit is actually working?

The speakers have two wires coming from the head unit. They aren't a common ground like some stock systems. Being that all the speakers don't get sound except a pop that would lead to a common issue. The head unit is common between them all.

Unless you have a factory system that has an amp in it. But you didn't state your year or trim level or anything, so its anybody's guess.

 

[Super mud]

Sorry forgot that. Also didnt know that the factory ever put amps in. It's a 87 laredo so it's an 8 speaker system though the original owner added 2 tweeters above the dash and replaced the rest (except the 2 behind the under dash panel) with pioneer and jvc speakers. What I meant by the head unit working is that it is visually functioning like it should.
Also what do you mean by the head unit is common between them all?

 

[Talyn]

You don't have a factory amp.

All speakers are not working. they don't share any wires, so the only thing that links them is the head unit. This is what I mean by the head unit being the common item. Make sure the head unit is getting good + power, has a good ground, and the wiring harness is plugged in securely. . If those items check out the head unit is bad.

 

[Super mud]

Damnit....ok thanks for the help lol.