ampeg gemini 2 weak reverb

[river rat]

Hi, I"m a new member and not well versed about electronics...That being said , I have a problem w/ the reverb/ echo on my 65 gemini 2 amp .
The reverb used to be as deep as a well .After being stored for a couple of years, the reverb is barely audible. What gives? Any help is greatly appreciated.

[Iceviper]

Is it a G-15? These amps use a pretty high B+ so if your not well versed or comfy you probably should steer clear. Also, some test equipment would be very helpful. You can check to make sure all the tubes are lit for a start.