Yep. Just measure the battery voltage running and not running. Off, you'll get somewhere between 10 and 12 volts (never over 12) depending on how long it's been since it ran. Then start it and the voltage should measure somewhere between 13 and 14.5. A bad alternator will measure the same running or stopped (less than 12 vdc). You can use either a digital or analog meter for this. The change is much more significant than the actual number read. You can sort of estimate this by looking at the headlights running and then stopped. They will noticably dim when your assistant kills the engine if the alternator is working properly (switch to accessory mode since Volvo kills the lights in OFF position.) Again, no change means no charge.

Many high mileage alternator failures, particularly ones where it's intermittant at first, are due to worn brushes which on many alternators is a screwdriver repair and under $50 even with a dealer part.