In all reality, it'll be nearly impossible to find a used controller. It's the most expensive component in the entire machine, by a large margin, and it's really the only bad part that would keep someone from fixing up any other issues with one. That's where I am, with 2 of them...
Even if I found an E2 Blue dirt cheap (they're out there), it would be wiser to just fix the issues with that machine, versus swapping the controller into a Gold that's not worth as much, nor designed as well. The only possible way would be a Blue that is literally destroyed on the outside.
Finding another dirt cheap Gold will raise more concerns. Does it have an updated controller? Doubtful, meaning its days are probably numbered, no matter how well it runs when it's acquired. Anyone who knowingly paid the money for a new $300 controller won't be selling the machine for much less than that.
In the end, I have some good parts. I may keep them for fixing up future acquired machines, or sell some of the parts. I got my money's worth with some accessories I needed for my Blue, including the 4 qt basin (new), inlet cover (new), inflator/deflator tool with coil wand (new). There are 2 good separators, latches, seals and motor units, hoses, wands, power nozzles, dollies and a few other attachments. There are some other accessories for an Aquamate and others. For $50 for everything, I knew I'd be ahead, even if the machines were toast.
