Roland JC-120 multiple pops at turn-on

[Snithcl1932]

Getting multiple pops when turning on this amp in vibrato or chorus mode.  Multiple pops signal first detected at last IC stage of vibrato prior to going to power amp stage.  Has anyone seen this?  Is this just a normal occurrence for this amp when powering up in this mode?  When in the normal mode, I only hear the normal turn-on pop.  Of course, the vibrato circuit is not connected to the power amp in this case.

[J M Fahey]

What happens if you turn it on with all controls set to 0 ?

[Snithcl1932]

What happens if you turn it on with all controls set to 0 ?

It happens with all controls set to 0  and nothing plugged into amp.