Quote:
Originally Posted by timmy
So with doorknob capacitors, how can you tell if they are going bad , like symptoms, since you really can't tell by just checking them without hv running threw them. Do they become intermittently problematic ?
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I've seen doorknobs dead short on a dime and I've seen them go flakey where the HV will fluctuate between almost normal and dead (horizontal will act flakey due to the extreme load fluctuations)....
If there is dag on your glass CRT and it is grounded then you can remove the doorknob and power the TV to test it (the doorknob is likely redundant). If the set opperation improves substantially the doorknob was bad.
If you disconnect it put a glass or ceramic ( a jar or coffee mug often works) insulator in place to prevent the disconnected end from arcing.
In the early 50s many sets that didn't need a doorknob would have one.... many TV makers would have one chassis drive a wide variety of CRT sizes and if one of those CRTs was metal then every chassis made would have a doorknob.