Hey Otis, i just got one of these from a guy off ebay and after 4 days the capstan motor went bad...i'm still waiting to get one, also the right side tensioner assembly was incomplete so the tape sort of took up the slack a little roughly...i fixed and re-lubed the tensioners and now they are smooth as ever....these machines are pretty finicky...but the owners manual has all the testing and calibration procedures in it.
Audio Tape Recorder Heads that have gone BAD !!! here is a cool page for inspecting heads....
as far as tape goes, the guy i bought it from said RMG900 on a 10.5 x .5 reel is what my machine is set up for....he said this
The RMG 900 needs a lot bias 6-7db @ 10Khz. Its also set up for 370nWb/m +6Db. So its operating with this tape correctly. and that no dbx was necessary, for the few hours it worked, it seemed to sound quite good...
uh crap...nevermind 388 doh!