HOWTO: OEM Audio Amp Repair - fix buzzing/noise/no volume!

Looking through the forum, I've seen several threads on audio amp issues, and there seems to be a pretty common issue with our amps. Either there's a noise at low volumes (alternator/spark noise) or the volume is much reduced, or both. I had the same problem (both) recently, and decided to figure out why the amp failed. Turns out, all that was wrong was that the small 5mm capacitors in the amp were going bad. Bad caps are a fairly common thing in older electronics, and fortunately they're pretty easy (and cheap!) to replace.

If you know how to use a soldering iron, you should be able to fix this yourself. The parts should cost less than $20. Even if you're not that good at soldering, there are lots of YouTube videos that will give you everything you need to know, and this will be good practice.

Even though it's easy, it's a little tedious, so give yourself 3 hours to do it. It'll be worth it.

Here's what you will need:

• Safety Glasses
• Soldering Iron
• Solder (use the thin electronics kind- the plumbing stuff is way too thick for this)
• Screwdriver (Philips #2)
• Needle Nose Pliers
• Solder Sucker (You can get this at Radio Shack, see YouTube for how to use it)
• 9x 10uF 50V electrolytic capacitors
• 18x 1uF 50V electrolytic capacitors

I had bought my capacitors here: Futurlec.com as part of a different project, but you can get them wherever. I didn't use exact replacements, some of the OEM caps were 3.3uF, 4.7uF, etc, and I just replaced all those with 10uF. I just used what I had and it worked out fine. If you want to be Type-A and use the exact values, be my guest, but using only 1uF and 10uF didn't alter the sound as far as I could tell. Just make sure they're 50V or higher rated.

1. Start by removing the amplifier from behind the passenger kick panel. There is a plastic cover, the kick panel, right next to the passenger's feet. Remove that. It may also help to remove the black panel above it to give yourself some room. Just pull on them and they'll pop loose- there are no screws holding them down.
   Remove the connectors from the bottom of the amp, black and grey. Then remove the two bolts holding the bottom of the amp to the car's frame. There is one more bolt (a nut, actually) at the top of the amp. It's tricky to get to, but you only need to loosen it. There's another wire harness in your way that you can release by pulling straight down on it. I was able to get to the nut using a ratchet, 3" extension, and a universal joint. DO NOT completely remove that nut- once it's loose you just slide the amp off the stud. You don't want to have to get that nut back on there, trust me.
   
2. Open up the amp by removing the four screws on the long edge of the amp, and then the four screws from the top bracket (the side without connectors). The circuit board should slide out of the case still connected to the top bracket.
   
3. Locate the capacitors you will be replacing. The pictures show all the 1uF caps circled in red, and the rest that I replaced with 10uF in yellow.
   
   
   
   
   
4. Before trying to yank out the old caps, straighten out their leads. Safety glasses are really important here! Heat up and melt the solder joint around each lead and use a tiny screwdriver or your pliers to straighten out the lead a little. It doesn't need to be perfect, just close. Please don't use the soldering iron tip to pry at the leads- this is a guaranteed way to get a face full of molten solder.
   
5. With your pliers, grab the body of one of the caps. They're weak and squishy, so don't squeeze too hard. On the opposite side of the board, Use your soldering iron to heat both leads of the cap simultaneously. Pull gently on the cap to free it from the board. Don't pull hard. If it's not coming out, the solder is not melted yet. If you pull really hard you will pull the plating out of the hole, which would be very bad. You should actually add more solder to help spread the heat- it makes it much easier. You will probably end up squashing and maiming a few of the little buggers, but that's okay. It's their fault you're doing this in the first place and they deserve it.
   
6. Use your soldering iron to heat each hole from the top of the board, and use your solder sucker to clean out the hole from the bottom. When you're done, each hole should be clear of solder and ready for a new capacitor. If you encounter a hole that you can't clear out, try poking a regular straight pin through the hole while heating it with the iron.
   
7. Insert the correct replacement capacitor to each location. Refer to the picture above if you've forgotten which goes where. After threading the leads through the holes, you can bend the leads in opposite directions flush to the circuit board to hold it down.
   
8. Now solder those things down! Make sure to completely heat each joint and use enough solder to prevent a cold joint, but not so much that you're globbing it everywhere. Look at the other solder joints on the board as a reference. When you're done, clip the leads close to the joint to make it look all professional-like.
   
9. Reassemble your amplifier and reinstall it in your gorgeous TL. Remember to reconnect the wire harnesses and tighten that annoying nut on the top bracket.
   
10. Go for a drive and enjoy your newly-restored audio with no weird noises or buzzing. Party like it's 2004. Or '05. Or whatever year your TL is.