Type 111 capacitor replacement
Craig Sawyers <c.sawyers@...>
Hi all
I've uploaded a couple of pics to the pictures section of the Tekscopes site showing the replacement of the 40+40uF @ 450V smoothing cap in the Type 111 pretrigger pulse generator. The original was a Sprague unit, with a nylon insulating sheath. At least one lister contacted me reporting a similar failure with a Sprague cap in his oscilloscope, so perhaps this isn't unusual with these Spragues. The replacement is a JJ cap (Slovakian) that I got from a local supplier in the UK (although they seem to be available in the US and elsewhere too, just trawling google). JJ are a part of Tesla, who manufacture audio tubes. I used a 50+50uF @ 500V cap, and is exactly the same diameter as the Sprague unit, but a trifle shorter. What I did was remove the old cap from the mounting plate by twisting the locating tabs and pulling it off. I then trimmed the plastic sheath off the new cap at the bottom revealing the metal can, and give the adhesive something to grip to. Superglue was then used to glue the new cap to the base. As you can see, it almost looks as if it is original (which was part of the exercise!). JJ's site is at http://www.jj-electronic.sk/. Craig
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