Trouble with Vibrolux Reverb, coupling caps ?

Hi Guys,
I have an old Vibrolux that is my favorite amp. Have had it for years. Its 40 some odd years old ,is in good condition and has been well maintained.
I have been having a problem with it for some months now.
I have static that sounds like dirty pots on several of the Knobs.
Both volumes , both treble's , reverb etc.
I first thought that it was dirt , so I sprayed them , no relief.
It seems highly unlikely that all the pots should go at the same time, so I'm thinking that its something else.
I have been told that its likely that some of the coupling capacitors have failed.
That sound right to y'all ?
Should I just change them all ? or should I check them ? and replace as needed.
My tech skills are OK. I can do , remove/replace kinda stuff , but I ain't no electrical engineer.
You help will be appreciated.

Sounds like you have this amp for the long haul, so I would check them and replace as needed. If you depend on it for gigs, a maintained amp will have replaced capacitors. To check the coupling caps, measure voltage between ground and both sides of the cap. The voltage will be high on one side, and near zero on the other (that's one reason they are in there - to block DC). Make sure you are on a DMM range that can measure a low voltage accurately. If there is and DC voltage there, it is leaking and should be replaced.
If the static noise persists, you should investigate the larger power supply caps as well.
They are not passing your guitar signal like the (smaller) coupling caps are, and require a little testing to determine if they are good, or just replace them out of principle due to their age. One method to check them is to lift one end of the cap and temporarily jumer in a new one to see if there is an improvement. If you have a capacitance checker, give that a try. Observe polarity on electrolytic capacitors.
The other small electrolytics (20uF/25V) used for cathode bypass have the same judgement call as the power supply caps. Sometimes, replacing those can have a huge change in tone and volume.
Be careful and discharge everything each time you power it up with a ~1k resistor to ground for a few seconds. If you're going to keep the amp or gig with it, it's refreshing to do it all at once and start with a clean bill of health and not worry about it for another 20-30 years. If you're going to sell, it's a good bargaining position that the service is done and has no worries.

Turn off all the knobs. Then turn one at a time. If you hear the noise on any knob, that tells you what part of the circuit has a problem. It's not always the caps either. There is a notorious problem with the resistor that leads off the reverb section. It helps to isolate one section at a time to focus on the errant part.

Try the volume knob on one channel with all other knobs at zero, if you hear the noise, its in the preamp section. If not, leave the volume at 6 and then work through the remaining knobs. If its treble, bass or mid, then its in the tone section, reverb knob indicates that part of the circuit. So on and so on. Now if you have no experience repairing amps, then take it to someone who has the experience.

Thanks Fenderlover and Middleman,
Thats a good start.
I'll get on it.
AW