gil wrote:
Any suggestions before going out and purchasing another tuner?

Check for a broken or shorted wire.
--
73, Cecil http://www.qsl.net/w5dxp



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When antenna tuner won't tune
 

I have the MFJ-971 portable tuner that I use with a random wire when all of
the sudden I could not load on any bands and the "forward" power reads very
low. At first I thought I blew the rig (TS-430) but then when I tried a
couple of different rigs ,the same thing happens... high SWR readings and
low power, also tried different antennas with the MFJ-971 and got the same
results.
Any suggestions before going out and purchasing another tuner? And is it
possible to "blow" a tuner, I dont use anything over 50 watts on CW.
Thanks.........gil

Are you sure it is the tuner and not just the meter circuit? Have you tried
another SWR meter? Check the diodes in the SWR meter circuit. They can get
fried by a nearby lightning strike. Replacement is easy is and cheap.

Oh yes, remove cover first.
--
Radio K4ia
Craig "Buck"
Fredericksburg, VA USA
FISTS 6702 cc 788 Diamond 64
"gil" wrote in message
...
I have the MFJ-971 portable tuner that I use with a random wire when all
of
the sudden I could not load on any bands and the "forward" power reads
very
low. At first I thought I blew the rig (TS-430) but then when I tried a
couple of different rigs ,the same thing happens... high SWR readings and
low power, also tried different antennas with the MFJ-971 and got the same
results.
Any suggestions before going out and purchasing another tuner? And is it
possible to "blow" a tuner, I dont use anything over 50 watts on CW.
Thanks.........gil

Gil,
As suggested, check the wiring (encluding the antenna).
If you aren't seeing any output from the '430 (or the other
ones) I'd also check the feed line between radio and tuner
if you didn't enclude that with the 'wiring' above. If
everything seems to be making good contact outside of the
tuner, then it's time to look inside the tuner. Look for
any obvious broken connections, black or burned spots, etc.
Switch contacts are a likely place to find problems, so
give them a good look. If all else fails, you might 'wack'
it between the eyes just for the hell of it, sometimes it
helps.
Can you 'burn out' a tuner with 50 watts? Yes, just
depends on the tuner...
'Doc

I wonder if the meter or the meter circuit got screwed up?
I connected the tuner to an outside SWR/WATT meter and it seems to tune the
antenna well....according to the outboard meter while the one on the tuner
itself reads high SWR and low power.

"gil" wrote in message
...
I have the MFJ-971 portable tuner that I use with a random wire when all
of
the sudden I could not load on any bands and the "forward" power reads
very
low. At first I thought I blew the rig (TS-430) but then when I tried a
couple of different rigs ,the same thing happens... high SWR readings and
low power, also tried different antennas with the MFJ-971 and got the same
results.
Any suggestions before going out and purchasing another tuner? And is it
possible to "blow" a tuner, I dont use anything over 50 watts on CW.
Thanks.........gil

gil,
Recheck to see if the input and output of the
tuner aren't backwards.
'Doc

'Doc wrote:

gil,
Recheck to see if the input and output of the
tuner aren't backwards.
'Doc

I gave the same advice to a guy once and he laughed, thinking
I was just kidding! It turned out to be the problem!
--
--------------------------------------
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--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada

Greetings

I must admit that was my first thought. Unfortunately I don't know if they
swr bridge is part of the tuner or not. But are either one connected
backwards?

Larry


"'Doc" wrote in message ...


gil,
Recheck to see if the input and output of the
tuner aren't backwards.
'Doc

Irv Finkleman wrote:

'Doc wrote:
Recheck to see if the input and output of the
tuner aren't backwards.

I gave the same advice to a guy once and he laughed, thinking
I was just kidding! It turned out to be the problem!

A similar thing happened to a friend of mine. He had his
antenna screwed into coax-2 and his switch set on coax-1.
Hint: Looking down on the back of an MFJ tuner, coax-1 is
not on the left.
--
73, Cecil http://www.qsl.net/w5dxp



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I want to thank all for the input. The problem seems to be in the meter
circuit, couple of guys mentioned the diodes could be shot?
There is no sign of anything burned up or broken, right now I'm bypassing
the meter and its components and just using the tuner with an outboard
SWR/Power meter.
What is the way of telling if the diodes are bad using a voltmeter? And
should they be removed before checking or can they be checked while mounted?

Again...thanks, you guys have been great help

Gil
"gil" wrote in message
...
I have the MFJ-971 portable tuner that I use with a random wire when all
of
the sudden I could not load on any bands and the "forward" power reads
very
low. At first I thought I blew the rig (TS-430) but then when I tried a
couple of different rigs ,the same thing happens... high SWR readings and
low power, also tried different antennas with the MFJ-971 and got the same
results.
Any suggestions before going out and purchasing another tuner? And is it
possible to "blow" a tuner, I dont use anything over 50 watts on CW.
Thanks.........gil