[R-390] Rebuilding C551 - BTDT?

[Craig C. Heaton]

Barry,

Gonna have to charge for the trade secrets, hi. I got lucky, Norvac, in
Eugene, OR had a NTE MLR205K630 hanging on a hook, the last one. It fits
inside quite nicely, and is a 2uF @ 630V rated cap. Also note: the mylar 2uF
cap works well.

The bottom of C551 is pressed into the top section and soldered from the
factory. Using a cutoff disk with the dremel tool takes care of this issue.
Turn the cap upside down and cut through the bottom end of the cap, not the
sides.  The only glitch in the get-a-long is what size bit/tap to use. The
old wire leads were crimped into the lugs. I filed the old leads flat/flush
with the sealed lugs. Might have to cut/file below the crimped section.
Then carefully drill out the old leads with a #43 bit and followed with a
4-40 NC tap. This should be small enough in any case so the drill bit
doesn't cut the old lug in half! Some hardware stores will sell the drill
bit/tap as one item.

A small machine screw and a solder lug will give you something to attach the
cap. Another small item, when cutting open the bottom of the cap, keep the
cutting disk depth to a minimum. Less oil is sprayed this way, its not PCB,
but who likes oil dripping off the walls. Might want to take this task
outside to keep peace with the spousal unit. Safety glasses, etc, correct
PPE........

Craig,


That doesn't sound too difficult.  I was curious if there were
any "gotchas" like not being able to find a cap that will fit in the old
housing or the housing is spot-welded to the frame in places where you
can't see it easily, etc.

Looks like I have some fun time ahead of me...

Thanks,

Barry