C20 and C21? Do you mean capacitors? Yes, it would be the same procedure as I mentioned above, but be aware as I mentioned before, a multimeter can only tell you 1 of 2 things about capacitors:
- It's definitely bad (shorted or open).
- It's maybe bad (looks normal on the multimeter).
A multimeter can't tell you that a capacitor is GOOD. Even if your multimeter has a capacitance range, an electrolytic capacitor can have its capacitance in spec, but its ESR way off.
Definitely need an ESR meter to tell if a cap is for sure good, and yes, you often have to remove them to test out of circuit even with an ESR meter.
This ESR meter is highly rated by people who have to deal with bad caps often: http://www.anatekcorp.com/blueesr.htm
You can also buy it here: http://www.flippers.com/catalog/index.php?cPath=3
I have its predecessor, definitely a valuable tool for repairing anything using electrolytic capacitors. Although if this is the only thing you plan to repair for awhile, rather than buying a meter, it might be cheaper to just replace the caps.