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Old 11-30-2014, 08:24 PM
old_coot88 old_coot88 is offline
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Join Date: Sep 2009
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The first guess would be a weak H output tube of couse. There's a 'quick and dirty' way to check it without subbing the tube.
Turn the set off for about 7 seconds, and back on. Does the width take a while to fill back out to where it was, or not? If it does, it's likely the H out tube.

(The '7 seconds off' test can also reveal borderline weak H osc., 3.58 color osc., Vert out, RF amp tubes, etc.)

Your set probbaly uses a 6BK4 HV regulator. In later Zeniths using beam triode (6HS5, 6HV5 etc.) regulator, a gassy regulator can cause loss of width. The only test for these is to sub the tube, even though it tests 'good' on a tester.

Last edited by old_coot88; 11-30-2014 at 08:32 PM.
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