So, I have a CRT monitor that has jittery vertical deflection. How would I go about diagnosing and repairing this? Is the flyback transformer at fault? Nope, the flyback transformer strictly controls horizontal deflection and high voltage generation. It’s also good to know the flyback transformer functions as a failsafe to prevent screen burn if horizontal deflection fails.
20200226/https://en.wikipedia.org/wiki/Flyback_transformer
20200226/DuckDuckGo crt vertical deflection jittery
20200226/https://www.repairfaq.org/sam/deflfaq.htm
Oh, so now this good CRT repair FAQ that I found indicates that indeed, the flyback transformer and other complexities are primarily elements of horizontal deflection. But, if vertical deflection is at issue, that is not nearly as much of a problem to diagnose because the frequencies are lower, and therefore the circuitry is simpler. Often times in newer CRT sets, almost all vertical deflection circuitry is handled by a single integrated circuit. That’s great to know! Because… as is often the case with such integrated circuits, all of the required circuitry except for capacitors are included in the integrated circuit. And with chips, it’s typically either all or nothing.
So, the answer is simple. I’m having trouble with vertical deflection being jittery, therefore I should look toward diagnosing the vertical deflection circuitry. But the vertical deflection circuitry still works most of the time, and we know it’s likely all contained in a chip, so that narrows down the problem to the few supporting discrete components that are outside the chip, and those are sure to include capacitors, and maybe a few inductors.