TC SCF gone noisy

springhead

I think my lovely old TC Stereo Chorus Flanger, P210, has gone noisy.  Still working ok but I don't remember it as having any hiss, which is does now when active or in bypass.  Although old, mine is the later version with the purple stripe on the front, single board with part SMD and part through hole rather than the original two board pedal.

It's not true bypass so there is a fair amount of electronics that could be causing it even when 'off' - couple of op-amps, a compander chip, the PSU etc. etc.

Anyone else had and fixed a noisy SCF?