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#1
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No more magic smoke.
My Zenith 11S474 console started making noises similar to putting a stylus on a bad record then died and started smoking. At least I know the power transformer is still good.
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Rick (Sparks) Ethridge |
#2
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Quote:
The only difference between the two is the first audio and detector circuit. The eleven tube job has a 6J5 and a 6F5 and the ten tube uses a 6Q7 for both functions. |
#3
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Quote:
If that ain't your issue, pull the rectifier tube, if that stops the smoke check the resistance to ground of the B+ rail. The resistance should be higher than the result of dividing the B+ voltage (probably 450V) by the B+ current (probably less than 0.150A). If the B+ to chassis resistance is low, go to each point things connect to the B+, unhook everything, measure the individual disconnected paths and follow the path of least resistance to find the short.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#4
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How did you determine the PT is still good ? |
#5
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After turning the power off I turned it back on quickly. 6E5 tube lit up. I know; not a good practice.
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Rick (Sparks) Ethridge |
Audiokarma |
#6
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You can HOPE it's still good , but till it's seen properly performing in real time operating conditions (like the repaired radio running an hour without the PT reaching Nuke plant temperatures) there is no automatic judgement of "the 6E5 lit so the PT is fine" . |
#7
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I completely agree with the rest of your advice. Do NOT power it up with the rectifier tube installed until you are confident that you've found and fixed the problem...If there is any rubber wiring remaining in the set I strongly suggest replacing it...You never know when/where/how it will short, and if you want to use the set regularly the rubber should go as preventative maintenance.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#8
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Both 6X5 tubes were previously replaced with solid state units incorporating surge suppressors. Before I reapplied power I felt the PS which was only mildly warm.
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Rick (Sparks) Ethridge |
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