Bit of a fiddly one this! I take it you are triggering the drum machine on Midi channel 10, selecting the Midi out port for the drum track from Cubase? The problem with general Midi is it only has channel 10 as a dedicated drum channel, and most drum machines only have the option of using channel 10. If you can select a different channel number on the drum machine, change the drum track channel number in Cubase to whatever you like, E.G. channel 9, and set your drum machine to channel 9 as well, and this will cure your problem. If you are trying to record the drum machine onto an analogue track, you could always turn the volume down on the device you don't want to record, until the recording is complete. Hope this helps, if you're still not sure, come back!! | 
