Hi, the switching mode power supply on my GK MB150S is broken. GK sent me the schematcs and i traced it down to the transformer primary winding insulation which is gone, killing the the two switching MOSFETs in front and blowing the fuse as consequence. This is the early MB150S with the first switching power supply 206-0071. So i would either need a new transformer T533 (C60-0025-02 BMI G525) or a new SPMS board 206-0071. GK said that the amp is obsolete so no parts available. Anyone knows a source which still has classic GK spare parts? Thanks!