So, there it was, the dreaded pop and crackle of the original sound system in my dear 2003 SAAB 9-3.
This sound system (AS2 150W Pioneer manufactured) is the second step of the original system and runs on 7 speakers on 2 amplifiers.
The first 4-channel amplifier is built into the CD/head unit behind the climate control panel. This drives the dashboard 3½” speakers and the rear 4″ speakers.
The second 3-channel amplifier, the AMP1, drives the door and center dash speakers and is connected via a fiber optic bus to the head unit and mounted with a single torx screw under the driver seat. This position is PERFECT for corrosion to appear.
This was my problem. Moisture had gotten into the amp and suddenly the dash and door speakers were dead, then alive, then popping and crackling, then dead again. This went on for a few weeks until it ceased completely.
Luckily, the other speakers were fine and the head unit worked normally so I could be sure that the optical bus line was running fine. I could therefore be sure that the AMP1 had a working optical input and power stage. If it hadn’t the optical bus would have been interrupted and entire sound system would have been dead and silent. I could get a replacement for $300 or so, but I decided, as a true electronics nerd, to take it apart and have a look.
Turns out it was one of the hole links through the PCB near the final power amp stage that had corroded on the top side and had no connection through the layers in the PCB. The bottom layer is painted with a water resistant coating, but not the top side. I cleaned up the corrosion with a fiber pen and restored the link by soldering in a peace of wire through the hole.
HEY PRESTO! It worked and no more trouble. It was a surprisingly easy fix and I am sure that I’m not the only person experiencing this problem, given the position of this amp.
Update – Many people are asking about pictures of my repair. To be honest I never took any pictures.
I have pasted together a little picture from various pictures around the web that illustrate how it MIGHT look when a via has corroded.
The left picture below show what I would call a suspect. Matte and dull. On the left picture the vias are shiny, with a nice coat of tin solder and are probably OK. This is NOT necessarily the position where the problem is for you, but I would say it is a real candidate to start looking. These pictures show the top layer, between the optics module and the power amps.