Rebuilding Can Capacitors

I included a few more pictures in this section.

I had restored my AU-11000 and the only thing remaining was the power supply filter caps.  There are 4 10000uf, 63v screw terminal capacitors.  I could find a few on manufacturers sites but no venders selling them.  The ones I found available were $56 each plus shipping and the terminal spacing wasn’t correct but I am sure they could have been made to work.  The real thing stopping me was I had 2 Chemi-Con KMH capacitors of the correct value sitting in my drawer and 2 more could be bought for $10.  Then I remembered a few years ago considering rebuilding some multi-section capacitors for a tube amp I had.  It involves cutting the bottom off the can, removing the insides and replacing it with new capacitor.  Since the new capacitors are smaller, they fit easily.  Here is what I did.

1/   Cut the can about 1/2″ above the bottom with a pipe cutter.

2/   The coiled plates of these capacitors are set in wax so I used a heat gun to soften it a little. Then by moving it back and forth I was able to remove it .

3/   The circumference the old plate coil and the new capacitor were the same so with a little heat applied to the new capacitor it slid into the old spot.  Everyone gets a little luck now and then.

4/   Solder wires onto the terminals of the new capacitor.

5/   Drill a hole through the connecting rivets for the wires.

6/   Feed the wires through the holes.

7/   Position the bottom with the terminals on the can and secure it with hot glue.

8/   Cut and strip the wires to the proper length and fasten under the screws.

It took me about 3 hours to do the first one and about 40 minutes to do the last 3.  I had considered soldering to the rivets but it just took to much heat and I noticed the rivet wasn’t really tight, it could be turned, so I thought it wouldn’t be a good connection.  The seams can’t be seen under the clamps.

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