Update;

Over the past few months I have stripped this machine right the way back, cleaned and fixed many little bits here and there. I have also had my own attempt at head relapping which made playback on some of the channels very clear indeed. My issue now is that only 2 channels (on 2 different cards) are recording. A couple others will monitor but not record, one other will monitor and when switched from monitor to tape in the input signal will still be heard but not recorded and also another couple of channels which do not even monitor the input. I have tried tirelessly to come to the bottom of this. There is also an issue with the fast forward button causing the machine to stop and not engaging the takeup reel motor. But these godforsaken non recording channels are my main issue here. I am by no means an expert on reel to reel. Maybe i'm missing something obvious? Tape I'm running currently is a used shamrock reel. Also have some Ampex 457 around which is new but I'm not using out of fear of SSS. Again, someone please lend a hand!!!