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Old July 29th 03, 06:08 PM
W5DXP
 
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Default Problem with my MFJ-989 and 1N34E

Francis Pinson wrote:
Is there anybody who have the same problem ?? And what kind of pin can I put
in place of the 1N34E ?? to find again the same characteristic of the MFJ
986 at the beginning ?? and be much powerful than the 1N34E ??


Sounds like the 1N34 reverse voltage spec may be being violated. Maybe
paralleling the 1N34 with a power Zener diode would help? The Zener
voltage should be a little less than the 1N34's reverse voltage rating.
--
73, Cecil http://www.qsl.net/w5dxp



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Old July 29th 03, 07:30 PM
Dave Shrader
 
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The 1N34s are basically Germanium devices with low forward voltages,
typically less than 0.3 volts. The 1N4148 and 1N4001 are silicon devices
with forward voltages typically to 0.7 volts.

You should be tracing the cause of the over voltage or overcurrent on
the 1N34s. Something else is wrong in the tuner/VSWR meter. Possibly a
shorted capacitor or shorted resistor in the VSWR sense circuit.

Deacon Dave, W1MCE

Francis Pinson wrote:

I have a problem with my MFJ-986

The two 1N34E of the control power and the system of TOS meter have qrt
....two time. I don't know the reason but it is not about too big power or
some thing like that....Not in use or in qso. I think it is with statics
(when there is a storm, or snow..or ??) I have also put 2X1N4148 and also
go qrt...

I have put two 1N4001 but all the measures of power or swr are wrong... I
cannot tune the god power. But they have no qrt for the moment !!

Is there anybody who have the same problem ?? And what kind of pin can I put
in place of the 1N34E ?? to find again the same characteristic of the MFJ
986 at the beginning ?? and be much powerful than the 1N34E ??

Thanks for your help and excuse me for bad english. I hope that you can
understand me !

Best 73

Frank **F6BLP**



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Old July 29th 03, 08:30 PM
'Doc
 
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Frank,
Write or email MFJ, they will be happy to
'trouble shoot' your tuner for you.
'Doc
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Old July 31st 03, 07:16 AM
Helmut Wabnig
 
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On Tue, 29 Jul 2003 14:30:21 -0500, 'Doc wrote:



Frank,
Write or email MFJ, they will be happy to
'trouble shoot' your tuner for you.
'Doc

With one year response time?


w.
--
On the Internet nobody knows that I am a dog.

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