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NotTaR of Television Sets : Origin of burn spot/line on projection s..  
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Origin of burn spot/line on projection set

This may be an issue where a set was repaired but with a blemish that you didn't think was there before.

(From: JURB6005 (jurb6005@aol.comtere).)

  1. If you fire a projection set up with one yoke disconnected AND the yoke windings are in series, unless you are quick, you will have a horizontal line burnt in all three tubes.

  2. The shop may have been less than 100% competent, and even if they were 100% competent, it could have happened at the actual time of the failure, before they ever saw it.

  3. If the set was fired up by ANYONE with any of the yokes disconnected, the vertical blanking circuit should have cut off ALL beam current, preventing the burning of the CRT screens. Two exceptions apply;