>
>I would say that the 160 meter padding caps on the tune and load are
>changing values due to heating....Most likely the load padders.
>
? the most likely answer. It could also be the Tune-C padders because
the current burden is virtually equal. To minimize tank drift, do not
tune up locked key. Also, the 800a7 has to be derated from 800mA to
600mA for locked key. Another prob. is that HV sags unrealistically
during locked key. For virtually all ssb amps, locked key is not where
one should be.
>My home brew "titan" has exactly the same symptom. (Same tank, same caps,
>same tubes). The tubes are new, and the filament voltage is right on spec.
>
? With barium migration there is a slow drop in anode current as the
grid temp rises. . With a drifting tank, anode current is virtually
constant. The great mystery is why the Titan's designers failed to read
the specs from the cap. manufacturer.
cheers, Jim.
>
>-----Original Message-----
>From: measures <measures@vcnet.com>
>To: Lane Zeitler <Ku7i@worldnet.att.net>; ve5sf@sk.sympatico.ca
><ve5sf@sk.sympatico.ca>; AMPS <amps@contesting.com>
To: <amps@contesting.com>
>Date: Sunday, January 02, 2000 15:27
>Subject: Re: [AMPS] Titan 425 Question
>
>
>>
>>>
>>>
>>>Rich said:
>>>
>>>> Firstly, I would try to determine if the problem is in the tubes or in
>>>> the amplifier. To make this determination, I would test the tubes for
>>>> abnormal leakage. To do this you need a +/- 5kV high-pot tester,
>>>> current-limited to a couple of hundred uA. . With +5kV on the anode,
>>>> you should be seeing under 10uA.
>>>
>>>Rich,
>>>What is your reference for this?
>>>
>>? Personal experience with 3CX800A7s and the 425.
>>
>>cheers, Lane
>>
>>>Ku7i
>>>
>>>
>>>>If the measured leakage decreases when
>>>> the anode is negative, you could have a bit of gold-sputtering -- which
>>>> is Not necessarily a fatal condition. Loose gold will definitely mess
>>>> with grid-current readings.
>>>> cheers, Sam.
>>>>
>>>>
>>>> - Rich..., 805.386.3734, www.vcnet.com/measures.
>>>>
>>>>
>>>> --
>>>> FAQ on WWW: http://www.contesting.com/ampsfaq.html
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>>>>
>>>
>>>
>>>--
>>>FAQ on WWW: http://www.contesting.com/ampsfaq.html
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>>>
>>>
>>
>>
>>- Rich..., 805.386.3734, www.vcnet.com/measures.
>>
>>
>>--
>>FAQ on WWW: http://www.contesting.com/ampsfaq.html
>>Submissions: amps@contesting.com
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>>
>>
>
>
>--
>FAQ on WWW: http://www.contesting.com/ampsfaq.html
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>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
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>
>
- Rich..., 805.386.3734, www.vcnet.com/measures.
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
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