OK, thanks for that info.
On this chassis, that 2/5 error code you're seeing is almost always caused by a defective power supply board, or a failed display panel. Sometimes it's the LED driver board, and in very rare cases, I've seen the main board or the FRC cause it, but only once or twice.
Since you've already replaced the power supply, main and FRC, you could try the LED driver (>>link<<). Considering how much work you've already put into this fix, I would go ahead and do the LED driver. It's about $50, and the only other possibility (that you haven't already tried) is the display panel itself.
The panel would be pretty bad news, sorry to say. Replacing the panel is possible but it wouldn't be cost effective. $1,000+ just for the part.
I hope that answers your question. Let me know if I can do anything else, and please remember to rate the service I've provided. I hope it was excellent!