Recently, my Sony Trinitron KV-21LT1B CRT TV abruptly powered down and wouldn't turn back on. The LED indicator remained unlit, and I heard no relays clicking; it was completely unresponsive. Diagnosing and repairing this issue took quite some time and effort. Therefore, I'm writing this brief post to share how I fixed the problem in the hopes that it might assist others facing a similar issue.
I began my troubleshooting process by initially inspecting the electronics for any glaring issues, such as leaking capacitors, shorts, cold solder joints, malfunctioning voltage regulators, or problematic diodes. There were no apparent problems like that to be found, so I needed to dig a little deeper.
Let's get straight to the point. After some searching, I stumbled upon a magazine scan on WorldRadioHistory that provided detailed technical information and repair advice for the Sony FE-1 chassis on pages 16-21. It suggested checking IC609 (TOP209) and the surrounding components. When I read about IC609's responsibilities, it seemed like a plausible culprit, and indeed, it was. I replaced IC609 with a new chip, along with R627, which had readings slightly out of spec. After these replacements, the TV fired right back up!