[Boatanchors] How to recap bathtub capacitors?

[Al Parker]

Hi Sven,
    Most of the bathtubs in the SP-600 are 10mf at 100v, and most of them get 
leaky.  3 in the -50v bias supply  will make operation lousy.  So, 
replace/restuff them all, and check the 3 associated 10k resistors.
    I use a propane torch to open them, but do drill 2 small holes in the 
can's cover to release any pressure buildup and to let any oil drain out. 
My metod may be sort of like a blacksmith, but I hold the can with 
slip-joint "water pump" pliers while it is being heated, then when the 
solder flows I rap it on a piece of cardboard on the floor.  That usually 
knocks the solder out and makes it easy to pry the cover off.  It's a good 
idea to wear rubber gloves to keep the oill off your skin.  I do not know if 
it is PCB or not, but I am careful.
    All of the bathtubs can easily be replaced with discrete caps, which are 
very small and won't be noticed among the other new ones you put in.  The 3 
bias ones can be put on 2 small terminal strips in that area.
    You can see some pix of my process on my webpage, 
http://www.boatanchors.org/filtercap.htm and also see some of the 
electrolytic re-stuffing I do.  There are several complete SP-600 jobs that 
you can see on the site also.
73,
Al, W8UT
New Bern, NC
www.boatanchors.org
www.hammalund.info

----- Original Message ----- 
From: "Sven Grandell" <sierra.victor at telia.com>
To: <boatanchors at mailman.qth.net>
Sent: Sunday, February 24, 2008 11:49 AM
Subject: [Boatanchors] How to recap bathtub capacitors?


I am ready with recapping of my SP-600 but the bathtub capacitors.
Some of them leaks but it is perhaps a good idea to recap them all.

Should be glad to get some tips how to open those cans.
I know there is a possibility for PCB-oil in them so had to be careful.

Sven, SM3SV
_______________________________________________