i have owned my t-dac & t-drive both mark 2 versions for several years used via balanced xlr connections and AES digital to t-drive very happy with sound for the vintage of components.Due to t-drive not reading certain discs and skipping i purchased a Meridian 506 20 bit secondhand to use as a transport via coax digital output to t-dac but discovered that coax digital outputs of t-dac do not work i have never used them before.Does anybody know of this problem and if it is easy to repair and possibly upgrade also the problem with the t-drive is this the laser or does the mechanism need cleaning or tray need cleaning oiling.I would greatly appreciate some advice.