Looking at the seller, I initially thought it was a distinct possibility.
However, in this case it's unlikely. All the VCFs had the same batch number, as did the EGs. Something must have caused them to go, and accusatory finger first pointed to the PSU; but I don't think it is over-voltage. The voice board has a constant 10v as it should.
When the new ones arrive I'll test them carefully comparing them with the scope, before giving it a full calibration.