Wow.
This capacitor doesn't provide power to anything, and the MFJ-989C doesn't have
an S meter.
It would not be rated "3kW," as capacitors aren't rated that way at all.
It's actually a low voltage variable capacitor used for compensation to help
SWR meter accuracy. Making it adjustable is a good idea.
It's a very small capacitor on the SWR bridge circuit board and one of these
shown on this page might be similar:
https://www.electronicsurplus.com/capacitors/variable-capacitor Even at
1500W applied RF power to the tuner, the voltage across that capacitor will
never be more than about 100V assuming the tuner is adjusted for a match so the
XMTR side of the bridge will look like about 50 Ohms.
If you call MFJ they probably stock this component and it might be easy to just
buy a direct replacement.
-----Original Message-----
From: Amps <amps-bounces@contesting.com> On Behalf Of A Lawrence Fibich
Sent: Saturday, September 24, 2022 11:24 AM
To: amps@contesting.com
Subject: [Amps] suggestion/recommendation wanted for a 'tunable' 15 pf
capacitor on MFJ 989C tuner
There is a tunable ceramic Capacitor listed as 15 pf in these tuners. They are
on the RF output and provide power for the S Meter. Capacitors in the area are
rated as 3 KW - I have been unable to find a 'tunable' micro size and wonder if
simply using a 15pf 3 KW capacitor would work - don't know why a 'tunable' is
used and can't find one and unknown what voltage would work. No response from
MFJ. ? Any suggestions appreciated. Apparently with age ? and tuning up an
amp destroyed this part. Larry FSacramento CA areaW6EF
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