an audio problem in a dell laptop

This is a Dell Inspiron 3541 laptop. I got it from a pawn shop for $100.00 in good working order. This laptop has only 1 audio jack for both the stereo headphone and the boom mic. I use an adapter to separate the jack into seprite stereo headphone and mic input to record old cassette tapes into the laptop, to then burn them to cd's later. The recordings were working great except I had to keep a D battery next to the adapter plugged into the laptop. The audio jack was lose and was losing contact to the mic side. I found out that this laptop still had 2 weeks left to go on the original manufacturers warranty. I called Dell and they sent a tech out with a brand new motherboard. This dude is dumber then my 11 year old nephew and my nephew already knows enough about laptops to replace hard drives and memory sticks. I have been teaching him. This tech tells me that this is an audio out only jack. The users guide that I downloaded for this laptop says otherwise.
Now with the new motherboard in place I am having strange internal audio feedback loops. I can't take the main volume control past 50% without the laptop going into all kinds of crazy feed back loops. I can't audio capture any of this feedback loops with any recording prog or audio capture prog. I can hold my cellphone up to the headphones and audio capture the sounds that way. It doesn't matter what the mic volume or mic boost is set for, both can be at zero and I get the feedback. It also doesn't matter if the mic cross over to the output is checked or not. When the adapter is plug in I get both the internal mic and the external audio source (like the tape player) in both the headphones and speakers. I didn't have this feedback problems with the old motherboard. Just a loose jack, like a cold solder joint on the motherboard. The warranty just ran out Nov-18-16 at 12 midnight. OOOO I tried uninstalling the new sound drivers that the tech installed and reinstalled the Win7 generic sound drivers. No change. So now what?

Steve

It doesn't matter if the internal mic is muted, disabled an the cross over to hear the mic is checked or un-checked. Now I can watch movies and play games still but the master volume is set for 50%. The sound is very tinny and the volume is just under the feedback threshold and sometimes tries to roll over. I will try and call Dell on Monday morning. Other then the sound problem the laptop works fine.

fireberd said:

I would think there is some type of warranty on the replacement parts, even if its past the warranty date. Have you tried contacting Dell?

The "tech" that was there to replace the parts is not a Dell employee. They use 3rd party companies for on-site service.

As far as the feedback, it sounds like possibly the internal mic (for the web cam) is always on and thus when the volume gets over a certain level you get feedback. Disable the audio for the web cam and see if that stops the feedback.

Finely after round, and round, and round I go and only God knows were it will stop. I finely found one of those indian's in the tech support phone center in india that understands and speaks very good english. I explained the problem. He didn't give me the standard brush off of "the laptop is out of warranty". We had to run through a few tests on the laptop just to keep his boss's happy. But in the end he told me this still is an open technical issue from back when the laptop was still under warranty. And a new motherboard is been sent to the local tech to install it. And I am going to run the sound board through it's paces while the tech is there this time.

Steve