That's an easy $50 fix. You could ask for half of it back, to be safe ($75 refund). And honestly, that's steal for the 9600/9800/9900 unit. Those really are worth a good $300 or more, so you already picked it up for half price!
The problem is that the input boards on JVCs are fragile is you plug/unplug/replug too much. It's why I use s-video extension cables on mine, which are always plugged in. I plug/unplug/replug from the extension instead. If those ever go bad, it's a simple $5 or less fix from
Monoprice.
Jots Electronics in Arlington TX is where our JVC decks have always been repaired. They repaired one for us back in 2012. I don't think they board had to be removed, just re-soldered in multiple spots. Stress separated some of the bonded connections. I'd have to fig out there tickets to see what was done, assuming there's repair notes on it.
If you're savvy with a soldering pen, you could maybe do it yourself.