I have the reverb on but no foot switch. Is that required to get the reverb on? Most amps I have used in the past, if you did not have the FS hooked up it just went by the controls on the front of the amp.  

As for the other questions:

1) measure DC resistance on input and output coils...
     Not sure what you mean. I have a volt meter, but forgive my newbieness, what are "coils"

2) tap the reverb case , do you hear some metallic springy noises?

Nope

3) touch the center pin of the reverb return RCA connector, do you get hum?

I toucheched the pin with my volt meter inside the reverb tank and I can here it get static. It might be worth noting as well that every time I switched this amp on with reverb up, it makes a horrible crackling noise for a second or two and then goes quiet.

Thanks again for helping me out!

Hello Forum, thanks for taking a minute to read my post. I am very new to amplification repair but always the DIY type and need some help.

I received a new Roland JC-120 Amplifier for Christmas 2008. I never tried the reverb before last weekend unfortunately, and low and behold it did not work. I called Roland and it is no longer under warranty and the closest repair shop is about an hour and a half away. So I figured I would open it up and see what could be obviously wrong with the reverb tank, i.e. broken spring or wire.

I did find a broken tiny blue wire inside the tank on the input plug. I soldered it back to where it was and fired it up. I still get no reverb. I have checked all internal connections OK, and everything else (chorus, vibrato) works perfectly in the amp.

So i am stumped and seek wisdom from someone who knows these amps. Are there any other things I try or check before I order a replacement tank?

Thanks in advance to any and all replies.

Cheers,

Joe