Analogue systems

Hi everybody

I'm new in this group and in the AS world.
As a quick introduction, I'd' like to say I'm a Belgian bass player
and vintage synths lover (my favorite one is my EMS Synthi AKS).
I recently bought a used AS RS-200 sequencer (standalone version, with
the RS-150 and RS-280 modules) in good condition, and will probably
soon buy the small System 01 that is for sale too from the same guy.
It's a nice basis to start with the cable modulars, that can be
extended later...

The RS-200 is a great machine, but mine seems to have a bug with the
start/stop button.
When I turn the RS200 on, sequence starts immediately running, and
pushing on the start/stop button doesn't stop it. This button has no
effect. 
But patching a CV in the related EXT input has some effect.

Can another RS-200 user let me know if it is well a bug of the button
(and if possible how it should be fixed) or if I missed something in
the manual about the use of this button ?

Thank you very much.

Constantin