Before I continue, I'd just like to apologize for the bad photography. My camera is about 10 years old, and the camera I bought to replace it was even worse.
Okay, so in some of the previous photos you'll see the short trace coming out from the contact traces. Just beyond that, you'll see a hole in the board. This is where one lead of the capacitor should be, but there's nothing to solder it to (except for a tiny pad on the underside). In this type of setup it's often best to solder both sides, once again to ensure a good connection. Repairing this trace and providing a surface to solder the capacitor to is very simple. First things first, cut the copper tape to size. I also trimmed the corners to round out the end over the hole. This ensures that solder won't "leak" over the edges as much and accidentally make contact with another trace.
(Don't worry, I got rid of the scrap on the contacts before finishing it up)
After the tape was stuck down, I used the tip of the exacto knife to cut a tiny hole in it so the capacitor lead can fit through.
And we're ready for the capacitor!
It was very difficult to read the label on the blown capacitor, as it was burnt and discolored. Thankfully the service manual (
http://cp.literature.agilent.com/litweb/pdf/01741-90911.pdf) is in public domain and I was able to find it easily with a quick google search. I looked at the schematic and found that the capacitor I needed was a 100uF one, but there was no mention of the voltage. The capacitors around the damaged one were rated for 35v, but from what I COULD read on the label of the blown one, it looked like it said 50v. I decided to buy a 63v one so I'd be covered either way.
I forgot to snap a photo of the cap before installation, but I'm sure you all know what a capacitor looks like. I soldered it to the board and finished the tin coating of the short trace. The cap is in!
In the second photo, please note the 1-2mm space between the capacitor and the board. This allows for air circulation and better cooling. If the capacitor gets too warm, the electrolyte will dry up and it will fail, possibly in the same way as the old one did.
That's pretty much the end of the repair process. Time to put it all back together....
After trimming the capacitor leads and reinstalling the contact hardware (front and back):
I had a spot of bother putting the knob back in, as mentioned a few posts ago, but I was eventually able to figure it out. I reinstalled the board to its socket on the main PCB and tightened the set-screws to make sure the knob doesn't slide out.
And we're set! Moment of truth.....
et, voila!
Beautiful! Needs a bit of tweaking here and there, but it all seems to be working as expected!
So that's it, a brief explanation of how to repair corroded traces on a PCB, as well as the replacement of a blown capacitor
I wish I was a better writer and that I could have made this more interesting, but hopefully all the necessary information was provided and that someone else can learn from my experience
If anyone's got questions or comments, I'm happy to answer them!
Thanks for the interest!
Best wishes and kind regards,
Matt