Shut valves do not turn water back on
Hi
I have been doing some simple faucet repair in the last week. But after I turned off the water to the bathtub using older style shut off valves under the tub, I could not turn them back on. (No water to the tub.) One shutoff valve handle turns without ever stopping, while the other turns only a few degrees in either direction and then stops.
Can I repair these myself? Or do they need to be replaced by a plumber? (It's a very tight workspace and I doubt I could solder in new valves.)
Also, why would these valves stop working? They were installed in a new house 17 years ago and have never been used until I turned them off. One use seems strange for one valve, let alone two.
Thanks for any advice.