NAD and some cab/speaker questions

[Holy-diver]

picked up a tremoverb head and Mesa OS cab for a really good deal. It’s in great cosmetic shape. The clean and gain sounds are on point but there are a few issues and questions maybe a forum member knows
Firstly the issues: reverb is non functioning and emits an awful noise when turned up and the tremolo doesn’t work. Any ideas what could be the issue?
Second, the cab. It appears to be an older one with rough tolex but a few things I am not familiar with. It is labeled a 4kb instead of fb and google isn’t turning up anything but it says on the back panel 25w celestion 100w total. I checked before I took it and it indeed has greenbacks but I wasn’t aware they made an os with greenbacks. Any insight would be appreciated
Anyways it looks sick and sounds great!

 

[cardinal]

For the reverb, mine does that if the two reverb cables plugged into the chassis are reversed.

Can't help with the other stuff.

 

[311boogieman]

Those reverb circuits can get get cranky so that along with your cab question I would probably be emailing Mesa (Gibson).

But you could also try messing with the fx loop/level/tube. Otherwise, you could claim that the product does not work as advertised.

 

[Holy-diver]

I got the reverb to work by cleaning the amp and potentially changing the preamp tube, I didn’t mark them before I took them out and they are all stock ?
The tremolo still doesn’t work tho. I’ll post a clip here soon either way