RE: [TCML] Burnt Joint (Cap Bank)

["Phil Tuck" <phil@xxxxxxxxxxx>]

Michael,
You need to physically anchor all of those 12 red 'trailing leads' to the
board. Either by wrapping some wire around the lead itself and then through
the board's holes, close to the edge of the board, or a spot of 'Hot Glue'
to tack them to the board. Otherwise they are relying on the soldered
connections everytime the leads move or flex.
The original trouble, as the others say, was a 'dry joint' (solder not
properly melting onto the wire, or only being held there by the resin in the
solder)
I have used that board to mount a string of diodes once, to rectify 10kV,
and the board ending up tracking. I had to put it under oil to allow it to
work (it was just a temporay test setup anyway).

Regards
Phil Tuck

www.hvtesla.com

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Michael Gray
Sent: 04 May 2013 22:05
To: Tesla Coil Mailing List
Subject: [TCML] Burnt Joint (Cap Bank)

I fired up my (first) TC for the first time today, after months of putting
everything together. Needless to say, it didn't work! I was slowly turning
up the variac, the spark gap fired up, and then I saw some smoke coming
from the cap bank. So I powered down and investigated - turns out one of
the soldered joints had smoked. I kinda regret buying the caps I did, the
legs on them are tiny and this makes it difficult to string them together.
The caps are mounted on some Vector prototyping board, and because the legs
are so small I've had to solder a very small length of high voltage wire
between each cap. I'm looking for some advice really on my cap bank - is
soldering prone to burning out like this? What's the best way to make the
connection? Should I try to solder the legs directly together instead of
using an adjoining length of wire? Should I invest in different caps?

The caps are rated at 0.047uF at 2kV:
http://uk.mouser.com/ProductDetail/Kemet/PHE450SD5470JR06L2/?qs=s4t14sB06yQT
V0lacTv0rw==

In 6 strings of 10 their total capacitance should be in the region of
28.2nF.

Here are a couple of pictures of it, you can see the burnt out joint on the
right:

http://imageshack.us/photo/my-images/841/20130504212930.jpg/
http://imageshack.us/photo/my-images/713/20130504212952.jpg/
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