If you're digging it up for new landscaping, you may just want to start from scratch. The tall heads in the corners look like shrub misters. If that's what was supposed to be watering the grass, they probably didn't help it much.

If the valve has a busted solenoid, it might be worth replacing. The diaphragms wear out over time due to abrasion of water and then they either don't open or close right, then it's digging it up and repairing - the diaphragms aren't all interchangeable, so you have to ID the brand, get the part.... If there were roots wrapped around it, then it probably wasn't in a box anyway.

Are you re-doing grass, or grass + shrubs? I'd figure the landscaping first, then put the sprinklers in to fit that.

Where are the wires and the control box? I think they're 24 v AC circuits, not a typical DC converter wall wart. Just an FYI if you're troubleshooting with a meter and wonder why there's no DC. Not that I've ever done that...