I've taken my GF525 apart and replaced the drive belts, but unforunately that wasn't the problem. On closer inspection, it appears that the tyres on the take up idler have turned to mush. They seem to have deteriorated to a sticky, tar like substance. I've attached a couple of pics and I just need confirmation that I'm on the right track. I guess the chances of finding new idlers is less than zero, but a couple of decent secondhand ones would do. Part number is NIDR-0066AFZZ. Any suggestions on cleaning the old ones/replacing tyres/anything would be welcome.