SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

You should have just bought two new 205's and replaced everything including the bonnet.

Try putting the old solenoids back on.
If that doesn't work you've done something wrong installing the diaphragms. Or..
You might have pinched off the small nipple on the bonnet.
Check for debris clogging the ports...

If you've never rebuilt a valve take a lookHERE for a short video on rebuilding valves

Nice video but there's a trick I've learned about rebuilding 205's
You need to attach the diaphragm to the bonnet with the screws first then attach the whole thing to the body.
Turn the screws until they're about 1/2 inch through the holes in the diaphragm. You need to hold the diaphragm tight because the spring will be pushing it out.
Then you carefully line up the bonnet and screws with the screw holes and quickly place the bonnet on the body. Keep your eye on the screws and screw holes.
Doing it this way insures the diaphragm doesn't turn and block the port and you don't smash the nipple due to the bonnet being out of alignment..

Good idea.
I might collect tips like that a do a 'special tricks' video, if time allows.