I have spotted a Durst M601 enlarger at a local auction house. Are there any particular things to look out for when buying this model 2nd hand? It seems to work fine with the Minolta lens stepping down OK. Only thing bothering me - & I'm sure it can be fixed - I obiously couldn't open it out in the showroom but when the light projects onto the baseboard it has black lines across it. I am assuming that one of the interior mirrors is cracked. Has anyone had any experience of replacing them? Cheers, FireBall