Hi, I've been mastering on a Sonic ssp system for about five years and had very little problems until recently. In the last few months the rate of CD's returned from duplication plants for "uncorrectable errors" has risen to about 20%. When I supply a new master cut on the same system the job finishes successfully but I'm concerned that my Sony 920 and 924 burners have seen better days. I sent test discs from both burners to a Clover Systen test this last week and was told that both drives show very low error rate until they get to specific spots and then go into very high error. But when the discs are run through the check several times they will pass the test on some runs. the guess was some kind of tracking error. Media is Taiyo Yuden silver74 min.Masters cut at 2x. Has anybody experienced these kinds of problems? Any solutions? Sure appreciate any help. Thanks, Rick Sutton