|To:||Ed Briggs <firstname.lastname@example.org>|
|Subject:||Re: [Amps] AL-1200 Pop|
|Date:||Wed, 7 Jul 2004 06:53:04 -0700|
On Jul 6, 2004, at 7:19 PM, Ed Briggs wrote:
It could be lots of things. But I recently had this problem and it turned
I do not see how a defect inside the tube could cause a flash in the RF out compartment.
Occationally, damage to B- clamping diodes. No carbon or other charring
That shoots down the bad blocker C theory.
Ed -- The 3CX1200A7 does have twice as much feedback C as an 8877 and 33% more feedback C than a 3-500Z. Does this AL-1200 have a "neutralization" circuit?
Dust, humidity, spiders and other bugs, finger grease on the tube chimney bent chimney clips Cracked or damaged blocking capacitor
If the replacement tube happened to have slightly less VHF-gain than the original tube, it would have less of a tendency to regenerate at VHF and cause HF tank arcing. On the other hand, VHF parasites normally increase the Ωs (ohms) of the suppressor resistor, but this one was reportedly within tolerance. .
My guess is that the tube was not defective, and that it had more VHF gain than average.
Not likely. Step-start currents are mild by design. / cheers
Richard L. Measures, AG6K, 805.386.3734. www.somis.orgor perhaps the light of the internal arc through the ceramic)
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