It sounds like you may have remote valves placed strategically throughout your yard or are they all connected in kind of manifold configuration near the house? It doesn't really matter but I added some callouts to what a remote valve inline with the water supply for each station looks like. Whatever yours are, they should have similar components?
You have replaced the solenoid and its o-ring
or whatever seal it had right? So let's assume that is now alright. If you have inline valves, they maybe a slimmer type that look more like an overgrown pipe fitting and the control knob may be different and even a large screw? The solenoid is in the top of the valve though.
See the little hex screw I have marked as the manual override? It is there so you do not have to run back to the controller when adjusting the sprinklers. Twisted open the valve floods as if you had switched the station on. If it is loose or its o-ring (or whatever) seal is broken it will allow the valve to open at least partially. Be careful to only hand tighten
or just beyond and especially if your valve is plastic or you could strip threads and have to replace the whole valve.
I am betting this is your problem.
Now then the other possibility is that the valve diaphragm and/or adjustment valve stem seals have had it. You should be able to get a rebuild kit for your valve. Make sure water to the valve is off and it will take you just a few minutes to replace it all. The kits should not be expensive.