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[Amps] al80a

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Subject: [Amps] al80a
From: (2)
Date: Sat, 3 Aug 2002 04:54:05 -0700
>Tom Rauch wrote:
>>> >is no good. I should have a known good one tomorrow to check it out.
>>> >In the meantime I have seen several things that need to be done.
>>> >glitch diodes, glitch resistor, new suppressor unit, etc. Live and
>>> >learn (or re-learn??)
>>99% of that stuff is just needless folklore originated by people who
>>sell kits.
>While rooting around inside the SB-1000, I checked the carbon resistor 
>in the paralytic choke... good as new.
**  What was the measured resistance? //   I have found that intermittent 
vhf parasites are so brief they can damage the element of a carbon-comp 
resistor without exhibiting damage to the moulded case.  Thus, a 
new-appearing carbon-comp resistor can have several times more ohms than 
its specified value.  

>>> Take care about the glitch diode. In an SB-1000 (same animal) that
>>> someone else had "pre-repaired", I had weird meter readings on 160m
>>> until the glitch diode was replaced with a 1N5408. It turned out that
>>> his no-name diode was rectifying at 1.8MHz!
>>He might not have installed the RF choke or the bypass caps, or used a 
>>diode with a low threshold voltage.
>The RF choke and bypass caps were there as standard. Since the screwy 
>meter readings were only on one band (the lowest) I put it down to RF 
>rectification rather than purely threshold voltage.
**  In your opinion, is 88-ohms of XC an acceptable bypass for c. 1A-rms 
of RF current?

-  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,  

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