K8RI-on-TowerTalk at tm.net
Fri Apr 5 13:47:06 EDT 2013
On 4/5/2013 12:33 PM, Missouri Guy wrote:
> I have to clean those rotary coils also. I use a contact
> cleaner on a rag. Press the rag on the coil and rotate
> the coil a few times to clean.
I used a pair of 989Cs for several years. Actually I used one of them
for quite a bit longer. I ran around 1200 watts from a 76A and a Henry
2K4 through them although the 2K4 was a project so it didn't get used much.
I used the tuners for sloping dipoles on 75 and 40 covering mainly 7.2
to 7.0 and 3.850 - 3.5 and the whole band on 160 with a half sloper
resonant around 1.825. Unlike others I had voltage problems on 160
instead of current.
As they were used a lot and over quite a range cleaning was a rare job
although they both needed it by the time I replaced them with the
Palstar AT5K. Wiping the coil with Tuner cleaner on a soft cloth worked
I wasn't comfortable running the DX-2sp through them. They'd flash over
occasionally running 1200 watts and I really couldn't turn the DX-2sp
loose so I had to be careful on tune ups. Hence the move to the AT5K.
If IIRC the instruction sheet says they are quite limited to power and
SWR on low impedance antennas (160).
> Charlie, N0TT
> On Thu, 4 Apr 2013 08:13:46 -0700 "Tom Osborne" <w7why at frontier.com>
>> Hi All
>> I have a MFJ-989C tuner that hasn't been used for a long time. I
>> need to
>> clean the coil as it is scratchy when I move it.
>> What is a good substance for cleaning the coil and wiper so it will
>> good contact again.
>> I just use this tuner on the number 3 radio at low power all the
>> time. 73
>> and thanks
>> Tom W7WHY
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