B7200 Front Hydraulics in the winter

[audiorecorder]

I have a 1980 ish B7200 with the front end loader attachment. This morning it's about 20 degrees. I got the tractor started but the loader is motionless. The tractor engine doesn't react when I push or pull the actuator controls. I topped off the reservoir with fresh fluid. I figured it may have needed to warm up as the engine continues to run. It's been about 30 minutes and no action. The rear hydraulics work fine. Where should I start?

 

[Egon]

Have you tried a heat gun or hair dryer on the control valve?