Further MMC woes.

["Garry F." <garryfre-at-xxxxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Well, after trying to replace the blown caps with all the spares I had I have a
worthless $84 MMC.
 
I built an MMC out of 3 strings of .033 uF caps at 2kv part number 940C 20S33K
from Mouser electronics. 15 caps per string.
 
I placed short pieces of thick plastic tubing around every other cap by
slitting the tubing length wise and slipping it over every other cap. This
effectively insulated every cap from its neighbor. Then I place poly sheeting
between the caps and the resisters and put generous amounts of silicone seal
around the ends to make sure there was no possibility of arching between the
solder joints. I used heat sinks to protect the caps from heat when I was
soldering the joints as well. Within 3-10 seconds after I hooked it up to my
tank circuit of a static air-cooled gap and a 12/30 tranny, a cap would blow,
throwing carbon all over the place. 
 
Also, I noted that resisters would BLOW as well, arching accross the body of
the resister as if it were a spark gap.
 
I know I got the correct type of resisters for I got the resister part number
from Terry and they looked identical.
 
I noted that the resisters would blow, and then when I snipped out the resister
the cap accompanying that resister blew.
 
All in all about 10 caps were destroyed as I jumpered caps and tried everything
I could possibly do to make this thing work.
 
As far as I am concerned, these caps are NOT suitable for MMCs and should be
avoided like the plague! If the caps were good, there should have been plenty
of other caps to take up the slack of the jumpered out bad ones to handle the
voltage easily but they blew and blew and blew. Many of them look like they
have been nuked. I watched one cap light up with dozens of sparkles as the
dialectric was machine gunned clear through.
 
By contrast, the EMMC cap that Terry Fritz sent had not blown but it does seem
to have quite a drift after a minute of operation, the coil seems to reduce in
power output.
 
The part number for the caps is a part number for caps that have worked in
MMC's but I got a note in the packing slip that the caps had been replaced with
equivalent caps instead of the original brown broad teardrop caps I was
expecting with these white tubular caps. So, it's the replacements they sent me
that are defective. I think that if they had sent me the caps I originally
ordered instead of these substitutes, I would have a good MMC.
 
To say I am disgusted is an understatement and if it weren't for a kind soul
here that offered to put together and test a multiple string MMC, I would be
quitting the tesla hobby. I do not think I will be ever attempting to make
another MMC myself. I do not think it would be smart of me to try this again as
apparrently, I am either doing something horribly wrong (I am pretty certain I
am not) or I have the worst luck in the world and am doomed to failure with
making MMC's. I will not invite the thief of bad luck to have a heyday with my
wallet again.
 
I feel like a fool, I feel like an idiot that doesn't know when to quit. This
in fact feels like what I imagine being hooked on gambling (Something I do not
do), as I hope the next near $100 bucks gets me something that doesn't go up in
smoke.
 
My only consolation is that maybe my extreme misfortune will save someone else
the loss.
 
I won't risk mucking up the market for all of you by mentioning a thing to
Mouser about this desasterous loss so I will keep my mouth shut. I will forever
wonder if I had at least called and asked nicely if they were aware of any
problems with the replacement caps that they might have replaced them or given
me at least a partial refund. I do suggest that when ordering caps, to specify
that no substitutions are to be made. I feel THIS was the cause of my failure
of this MMC.
 
Terry Fritz, Would you like me to send this MMC to you so you can look at it
and perhaps find out what the big problem with this cap is?