FWIW, I had two Tune capacitors arc. I sent them to Ten Tec and they were
disassembled. I do not know how they were repaired. The failures occured not
at the same time but two or years apart.
I believe the failures were caused by the damn cat sleeping on the amp. Cat
hair + voltage = big $$.
Mike
W8TRN
----- Original Message -----
From: "Bob McGraw - K4TAX" <RMcGraw@Blomand.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Sunday, May 11, 2014 17:07
Subject: Re: [TenTec] [Ten Tec} Centurion loading cap
I would not opt for putting anything on the plates. I would prefer to
polish the plates.
In the case of most of Tentec variables they can be disassembled. From
there some XXXX steel wool or jewelers rouge will polish the offended
plate. A Dremel is a big assist in polishing as well. If one can't get
jewelers rouge then use cheap tooth paste. The cavity prevention kind
doesn't have enough pumice however.
73
Bob, K4TAX
----- Original Message -----
From: "Hank P" <pfizenmayer@q.com>
To: <TenTec@contesting.com>
Sent: Sunday, May 11, 2014 4:20 PM
Subject: [TenTec] [Ten Tec} Centurion loading cap
If you reduce the air gap even with “insulation” the breakdown voltage
goes DOWN not up. Now sometimes , if the air gap is sufficient , the
“insulation” will modify the field of a sharp point or rough areas on a
surface enough to keep it from breaking down – but it’s the field
modification – not the “insulation” .
Don’t feel bad , others had not thought about that either - years ago –
on a military project – an air variable we had was arcing , and the
capacitor vendor said he had the solution , he made us a special by
putting teflon coating on the rotor and stator plates – it broke down at
a lower voltage than before !!!!! After the fact it was obvious – but we
all suckered ourselves in .
But having said all that some Glyptal or about anything that will smooth
that area – cover any sharp points and not decrease the air gap too much
may just work.
My recollection of that cap is it is made by TT or someone for them
with spacers and plates all bolted together – you might be able to get a
new plate/plates – or if you tore it apart you might be able to get the
area very smooth . If it is out near the edge you could just remove that
area completely and smooth off the cut edge .
73 Hank K7HP
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