Input problems on Akai 4000DS

[YooDooRight]

Can anyone offer me some help working an Akai 4000DS 1/4" reel to reel...

The right mic input doesn't record when tracks 1-4 or 3-2 are selected but works fine when Stereo is selected, the left mic input records fine (apart from an excessive amount of hiss) on all tracks. Is this normal?

I can basically hear the source material (bass guitar Di in this instance) and set a level for the right mic input in positions 1-4 and 3-2 but when i come to record, nothing, switch it to stereo and it records. Surely i should be able to record the left channel onto tracks 1-4 and the right channel onto tracks 3-2 right?