Hi All,

I have a couple of late model MFJ roller inductor antenna tuners with the
roller on the inside of the inductor. My old 989C with an external roller was
smooth as glass. These newer ones with the roller on the inside of the inductor
really are rough. They have a knob with a finger hole, but cannot be spun with 1
finger--you have to grab the entire knob to turn it. I have a 989D with a crank
type knob that has a slip clutch as part of the knob, and if you try and turn it
real slow, the clutch slips instead od the roller progressing slowly.

Has anyone "fixed" this problem with their late model MFJ ???


RON.....KA2IIA
================================================== ======
Remove the ZZZ from my E-mail address to send me E-mail.

On Wed, 31 Jan 2007 01:59:08 GMT, (Ron in
NY) wrote:

Hi All,

I have a couple of late model MFJ roller inductor antenna tuners with the
roller on the inside of the inductor. My old 989C with an external roller was
smooth as glass. These newer ones with the roller on the inside of the inductor
really are rough. They have a knob with a finger hole, but cannot be spun with 1
finger--you have to grab the entire knob to turn it. I have a 989D with a crank
type knob that has a slip clutch as part of the knob, and if you try and turn it
real slow, the clutch slips instead od the roller progressing slowly.

Has anyone "fixed" this problem with their late model MFJ ???

I fixed mine by just returning the 989D to AES -- they took it back.
My old circa 1992 989C is a marvel of precision, in comparison :-)

bob
k5qwg




RON.....KA2IIA
================================================= =======
Remove the ZZZ from my E-mail address to send me E-mail.

"Bob Miller" wrote in message
...
On Wed, 31 Jan 2007 01:59:08 GMT, (Ron in
NY) wrote:

Hi All,

I have a couple of late model MFJ roller inductor antenna tuners with
the
roller on the inside of the inductor. My old 989C with an external roller
was
smooth as glass. These newer ones with the roller on the inside of the
inductor
really are rough. They have a knob with a finger hole, but cannot be spun
with 1
finger--you have to grab the entire knob to turn it. I have a 989D with a
crank
type knob that has a slip clutch as part of the knob, and if you try and
turn it
real slow, the clutch slips instead od the roller progressing slowly.

Has anyone "fixed" this problem with their late model MFJ ???

I fixed mine by just returning the 989D to AES -- they took it back.
My old circa 1992 989C is a marvel of precision, in comparison :-)

bob
k5qwg

Last year the roller inductor on my 989C became a little bit dirty and
needed extensive cleaning after using it for several years at 1KW. I cleaned
it up but it was not easy. MFJ recommended that the only lubrication I
should use is pure graphite powder which I found available at the local ACE
hardware. It looks like it should be cleaned every year or so. That 989C
roller inductor is a work of art and MFJ sells replacements for about
$60.00. If I had a 989D I would probably buy a replacement 989C inductor.
When I checked other companies for their prices of roller inductors of
similar size/inductance/turns, they seemed to go for around $280.00, which
probably explains the EC for 989D.

On Wed, 31 Jan 2007 01:59:08 +0000, Ron in NY wrote:

Has anyone "fixed" this problem with their late model MFJ ???

I have an earlier "Differntial-T" model 986 that I bought in 1992. After
a couple of years it would get very stiff in certain places. I
disassembled it enough clean the grime out of the bearings and then used
petroleum jelly as "grease" sparingly applied. It still works very freely
and I haven't had to do it again.

I have to say that the finger dimple knob has not impressed me on the
later tuners when I've played with them at hamfests as they just seem
very stiff. Mine has the extra sub-spinner knob which works very well even
after all these years. Hopefully this 986 won't give up for a while yet,
but I only use it at 100 watts.

- Nate

--

"The optimist proclaims that we live in the best of all possible worlds,
the pessimist fears this is true."

One other possibility: tho dont know if they still
supply samples, and the stuff is SPENDY! An
outfit , in Portland Ore. has couple of products
geared to power companies/ electricians. It is
Cool-Amp , and has a powder that will silver plate
copper (and other) metals. They also have a
SILVER bearing grease called Conducto-Lube. and
as stated, would use VERY,VERY SPAREINGLY, but,
would lube a roller inductor's bearings,
provideing great continuity . Don't think would
be something you want to use on the inductor
surface, tho.
(this stuff made for knife switch and breaker box
repair, of high resistance problems) . Also great
for UHF/ Microwave DYA components, to silver
plate them ! Try Cool-AMP.com Even if cost
$5.00 for sample,
would be worth it! Jim NN7K


Nate Bargmann wrote:
On Wed, 31 Jan 2007 01:59:08 +0000, Ron in NY wrote:

Has anyone "fixed" this problem with their late model MFJ ???

I have an earlier "Differntial-T" model 986 that I bought in 1992. After
a couple of years it would get very stiff in certain places. I
disassembled it enough clean the grime out of the bearings and then used
petroleum jelly as "grease" sparingly applied. It still works very freely
and I haven't had to do it again.

I have to say that the finger dimple knob has not impressed me on the
later tuners when I've played with them at hamfests as they just seem
very stiff. Mine has the extra sub-spinner knob which works very well even
after all these years. Hopefully this 986 won't give up for a while yet,
but I only use it at 100 watts.

- Nate