Bose Radio With Amp/Sub Added, Was working, Now Stopped. Help?

[MrSlaybury]

Hello. Thanks to anyone taking the time to help me out. I'm not new to installs, but this one has me confused and lost!

Specs:

2005 Maxima - Bose w/o Navigation.

Stock Head Unit.

Alpine MRP-500 and Audiobahn AW1206T (4 ohm DVC) - Wired in Parallel to push 500 x 1 watts from amp. Sub is 1100w RMS.

Line Out Converter installed under rear deck, signal coming from factory subwoofer wire POST Bose Sub Amp.

8 Gauge Wiring - Ground under the mat in the trunk, scraped to bare metal.

I'm currently not getting any sound from the Audiobahn Sub except for one single "pop" when system is first powered on.

This install was working just fine for weeks, until recently. Sound came from AB Sub until the volume and/or gain was turned up, then sound would completely stop. Amp stayed on, no blinking light or any protection mode that I can see.

I detached then reattached all wiring, scraped ground area again, and NOW all I'm getting is the "pop" when system starts, nothing else at all.

The Sub and amp are second hand, and the sub does have a scratching noise when cone is pressed in until about 1", BUT it's done that when system worked too. I've tested the resistance of both coils and I'm right where I should be for both coils.

I've connected an iPod directly to the Amp's RCAs, still just pops once then nothing.

I haven't been able to swap any equipment out to test, that's my next step, one that I don't want to do (buy then return :/).

Well, I've turned to the experts here hoping someone has seen this issue before. This is my first install using a LOC, and I'm also thinking tapping into a Post-Bose Amp signal isn't my best option. Any tips there would be great!

So sorry for the book, but I am trying to be as detailed as possible so I don't waste anyone's time //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Thank You!

Chris

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[ObTechAudio]

I've done multiple installs off of Bose amps with LOCs. Many of them were on Mazdaspeed 3s. I never tapped into the sub output. I always went with a speaker for the LOC. I did one install three years ago and heard it just the other day. Still working great and sounds just like it did on day #1 . That's my first observation; tap into a speaker opposed to a sub (that advice could be completely wrong, but it's worked for my dozen+ Bose installs). Next, the problem you're describing doesn't really sound like a LOC issue, but rather an amp issue. The first thing I'd say is check connections especially grounds, but you say above that you've already done that. I find it odd that a straight iPod plugin doesn't produce any noise.

To troubleshoot, I'd unplug any form of an RCA, just the RCA, nothing else. I'd start the car and if I heard a pop, then clearly it's not an RCA issue, but an electrical. It sounds like something amp related. If you have a walmart in your area, just do the walmart special and see if it's your amp. What's the walmart special you ask? You buy something, use it, and return it for a full refund. I'd go buy a cheap amp there (usually it's like a Jensen) hook it up, and test is. If that pops, then it's something car related. Perhaps Bose related? If it plays and doesn't pop, then it's clearly a flaky amp connection somewhere on your motherboard.

 

[MrSlaybury]

Well...thank you so much for replying!

I figured the issue out. You are right: amp problem.

Basically, I spent hours teaching myself how to check the components on the amp's circuit board. First off, the ground terminal was loose, so I re-soldered and still nothing. Opened it up again and tested the resistance of the output and power transistors...

Problem: Blown power transistors.

So, I would really love to know exactly why they blew, but reading this AWESOME site created by an amplifier repair GOD has lead me to believe the ground being loose shorted the circuit and blew the MOSFETs. I'm buying a new amp tomorrow, and I really hope it isn't something else.

I will say, this website: Basic Car Audio Electronics is fantastically done. Definitely learned useful information.

As far as the sub vs speaker signal, I know now both can be used, and I found out exactly which wires I need to tap. Theoretically, the woofer signal should give me a better sound...I think. I'm going to try both when I install tomorrow and see what's better.

Phew...I'm just Amped up now....?