To: | amps@contesting.com |
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Subject: | Re: [Amps] 4CX1600B |
From: | "Ian White, G3SEK" <G3SEK@ifwtech.co.uk> |
Reply-to: | "Ian White, G3SEK" <g3sek@ifwtech.co.uk> |
Date: | Fri, 14 Nov 2003 18:05:23 +0000 |
List-post: | <mailto:amps@contesting.com> |
R. Measures wrote:
So "all that its cathode can possibly deliver" in this case is 3A... which proved sufficient to make the power supply go bang.
So I learned from that experience! No, still talking about my amp.The surprising good news was that the tube seemed completely unharmed.** He tried the tube again? RF-wise, the amplifier worked fine before the zener failed, and fine again afterwards. KL7RA's amp did the same after his component problem was fixed. He told us that his problem was due to the bias rectifier going short, so the original cause was probably something perfectly simple like a mains spike. Yes, he did. . -- 1Ampere pi-section 3-500Z grid to ground chokes are known to implode at the same time that a filament-grid short occurs. Some have speculated that the tube shorted, which blew the choke, but when a clip-lead is used to short a filament pin to a grid pin on a healthy 3-500Z's tube socket, nothing extraordinary happens, and the normal 0V-bias anode-I uneventfully flows. One clue to the cause of the implosion and short lies in the VHF parasite suppresor resistor because it typically undergoes a large change in R during a tube-shorting event, but without exhibiting any signs of external damage. That's an interesting statement to interject at this point - but in a real inquest, you'd be challenged to prove both its truth *and* its relevance to this particular dead amplifier. Otherwise it would be excluded as irrelevant. And so: ** The evidence may well be found in the autopsy. You and I have very different ideas about the valid uses of evidence, and indeed about what "evidence" even is... and we'd better end it there, before the moderators become nervous.
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