NSM fanfare selection problem

hi all, after faithful service my NSM fanfare 1958 clacker, has clacked out! problem being added selections to which you have selected...checked keyboard and wiring no faults...so the only thing left is the diodes that are in series with each selection coil? i have checked some of these and they do indeed read differently to each other...not sure if it is the problem, but i suspect it is...there are 120 diodes with 2 encapsulated in each so 60 items which are glued into slots in the pinbank with the hair like coils directly soldered to them....going to be a absolute nightmare to replace...got one out, and after much googling drawn a complete blank on replacements...any ideals anyone? i have included a photo the size is 15x12x3mm...bob