You will have to look around inside the amp to find them all. Most Fender combo amps have seven caps total. Either 7 single caps or 3 double caps and one single. Smaller amps like Princeton's may have only 6 of these caps. Tweed Fender amps will vary also, you will have to look at the amp to find them all. Some Fenders have one 25uf25v cap along the back of the amp near the reverb jacks.

They all need to be changed to new caps regardless of what amp you are working on. These caps make a huge difference in how the amps sounds and if they are over 10 years old they need to be changed. Sometimes the tremolo section has a 4.7uf cap instead of a 25uf cap. I replace these with a 25uf/25v cap or a 22uf/50v cap. Either cap works fine for a replacement.
Look at the Fender combo layout diagram above. This section of the layout diagram shows 6 of the 7 caps that need to be changed. The last 25/25v cap is next to the tremolo optoisolator and is shown in the drawing below left.

The first thing to do is remove the 25uf/25v caps from the circuit board and replace all of them with a new 22/50v or 25/25v cap. Unsolder the lead closest to the tube sockets and pull the cap up. The negative lead of some old caps continues through the eyelet and is soldered at the brass plate under the pots. Snip the lead flush at the eyelet, you will leave the section that goes from the eyelet to the brass plate. It's a ground wire that you need to leave in place.

There is one more electrolytic cap inside the amp on the bias board. It is usually a 25uf/50 volt or a 50uf/50 volt. It needs to be replaced also. I use a 47uf/100 volt cap. A 50 volt rating is not high enough for this cap. There is more than 50 volts across this cap, so it is a good idea to raise the voltage rating of this cap to 100 volts. Notice the polarity of this cap. The positive end goes to ground because this cap is smoothing out the negative voltage for the bias circuit.

After all the caps are in place and situated properly, go back and add a tiny bit of fresh solder to all the eyelets where you just installed the new caps. 

Remove them from the tube socket by carefully heating up the tube socket pins and gently pull each end free. Notice that Fender soldered them over the top of the tube socket. This is not a good idea because the resistor itself and the tube socket generates heat.
Notice in the layout diagram above I have hung them out away from the power tube socket. This method works great, I have never had to replace one of these resistors that I installed.

The small 1.5K 1/2 watt resistors are ok sometimes and sometimes they are burned up from the heat. Replace them also if necessary. They do not generate heat themselves so it seems to be ok to mount them across the back of the tube socket. Solder them high up away from the socket just to keep the heat from the tube socket to a minimum.