i have a f-100 212 combo that i picked up used and the reverb doesn't work. if i physically shake the reverb tank the springy sound comes through the speakers but the is no reverb effect when playing guitar. it came with a accutronics 9AB2C1B tank that reads 212ohms at the output and 1ohm at the input. i also tried with a known working tank model # 9EB2A1B which reads 196ohms at output and 56ohms at input. with both i can make reverb like noises by shaking the tank but there is no effect when playing guitar through it. i really like the amp and would like it even more if i could get the reverb to work. any help or suggestions are much appreciated.