Czarivey, If one can believe Abbey Road engineer Paul Hicks, the mono tapes are in good condition. As quoted from Sound on Sound:
Because of their importance, the analogue masters had been scrupulously maintained and archived. ÂAll the Beatles tapes are in fantastic order, the multitracks as well as the quarter-inches, enthuses Paul. ÂGuy and I have been doing Beatles stuff for about 15 years, on and off, and weÂve never baked a Beatles tape. The formula on that EMI tape was just fantastic. The only thing we did find, which we had to be incredibly careful with when we were transferring it  and especially with the monos, which hadnÂt been played in 40 years  was that a lot of the glue had dried up on the edits. So on the first wind-back you had to be incredibly careful, because a lot of the edits just split apart when winding. We had to get the gloves on!Â
ÂFor the transfer and archiving part of the process, we did it song by song, continues Guy. ÂSo if the tapes had come apart when we were spooling back, weÂd replace all those [splices]  same length, weÂd measure them all and make sure it was all pukka  and then song by song weÂd transfer them. WeÂd transfer the first one, go back, clean the whole tape path again. Beginning of each week, weÂd de-mag the heads. We had a speed reader on the capstan all the time so we knew it was running at the right speed.Â
ÂWeÂd line up and then weÂd always play through, manually checking the azimuth, says Paul. ÂIt was amazing just by tweaking that, if nothing else, how much more top end you could potentially get. That was a significant part of the transfer process.Â