Replacing Classic II capacitors

[howardc64]

I've got low audio and boot issues. Cleaned the board and now boots fine. Of course low audio issue is still around and definitely bad caps.

On the Classic II, there are a couple of capacitor in tight spots without too much room around it for a soldering iron tip. I've also read the traces tend to lift on this motherboard. Some repair shops won't touch this mother board anymore.

Thinking about ordering the capacitors and using the 2 soldering iron technique.

From those who has done the cap replacements on this board, is it more difficult than the other boards?

 

[crazyegg]

Hi All,

I am considering to get a surface mount hotair workstation from eBay. These things are selling for about $85.

This setup will allow for you to safely remove surface mounted caps and chips.

Regards,

ed...

 

[Unknown_K]

I use a single soldering iron recapping 2 Classic II machines. The space is VERY tight and on one unit i singed a plastic part doing the work. Lifting a trace happens on boards with battery leaks once in a while (chemicals weaken the bond holding the copper down), but you can glue the trace back down and solder bridge any cracks to make the system work again.

 

[tt]

It is hard to describe how I have removed the capacitors but I'll try. Use a pair of sharp diagonal wire cutters (side cutters) and cut-off the top of the capacitor. I made the cut as close to the base as possible. Then rotate the cutters 90 degrees and cut the remaining plastic/metal base in between the solder pads. When I cut it, the remaining bottom part yielded very easily, so i did not induce any damage. After that, desoldering the remaining two pieces was very easy.

Using two soldering irons or soldering tweezers will work also, but I err on the side of not overheating the board and its old components.

 

[howardc64]

tt, I was thinking about using your wire cutter method. Doesn't the Electrolytic Capacitor leak all over and make a mess when you cut it open?

 

[Unknown_K]

I use the cutter method and no there is nothing leaking. Cutting the cans pretty much pinches them shut anyway.

 

[tt]

howardc64, no it was completely dry. But in any case, I would recommend the board should be washed/cleaned afterward.

 

[howardc64]

Leaving a note for those doing this in the future.

Cutting the capacitor off method works great. Here is what you do.

- Cut the capacitor between middle and 2/3 way down. This gets rid of the top 1/2 of the metal casing

- now you have 1/2 of metal cylinder left. Cut vertically down the cylinder between the 2 electrodes. Gently peel off the cylinder pieces.

- get rid of the metal cylinder frame and the capacitor material inside

- There is a plastic plate at the bottom. Try to break it off in pieces rather than pulling it up. Exerting force on the 2 electrode post may pull up the circuit board solder pad.

- Now just unsolder the 2 electrode post

Very easy and I didn't lift up a single solder pad doing it this way.

The capacitor near the keyboard connector on the Classic II has no space to get a soldering iron in there. Furthermore, the surface mounted capacitors I got tend to cover up both the + and - pads. I had to mount this one side ways so I could get a soldering iron in there.

 

[tt]

Glad to hear it went well-- thanks for the additional details. It has been a few years since I did it, but I remember that it was very simple and gentle, even though at the time the process seemed counterintuitive.

 

[beachycove]

There are photos of the process described, with commentary, hosted here, running on the machine in question, a 68030-based pizzabox server.

What is especially amazing is how well that site runs.