Trinitron KD-36FS130 sudden issues

[YamahaFreak]

This set was working great for months until yesterday when someone finally agreed to buy it...just my luck, right?? Sometimes it powers up, sometimes it doesn't. When it doesn't, I get degauss and about 3 seconds of HV before it shuts down and throws a 5-blink timer LED code. Google seems a bit vague on this, with no specific incidences of this issue on my model. This TV has an onboard digital tuner, and it, along with the video inputs (at least the component inputs) were also not working just prior to the issue beginning. I had the set unplugged since yesterday and when I went out and plugged it in tonight, it started up...but still without any inputs or really anything other than the onscreen menu. Powered it off and back on, and I get the shutdown and 5 blinks again. This one has me stumped! It's been stored indoors and not moved for months, nothing changed about it or its storage conditions between then and now.

Also worth noting is that when it was working properly, the menu settings would all be reset every time it was turned off, regardless of if it was unplugged or not. Bass, treble, picture controls, all reset...and the built-in speakers are also turned off by default, which I found strange. It even loses the PIN for the parental controls when powered off, as if the PIN was never set up.