Hello everyone. I need to adjust record gain on Nakamichi MR1 but dont have a service manual. I've already did a head alignment but can't figure out which potentiometers are for record gain. Other Nak decks I have worked on have them marked. I need to know Left & Right EX rec gain,SX rec gain & Zx rec gain. I just need to know the location of the corresponding potentiometers. Thanks