Flat Lap Disk Question

[Michele-MD]

We have a Crystal Master Pro12 flat lap (magnetic disk type) and recently we are having a problem with disks flying off. These are not new disks. We have one disk that has a flexible back, it stays on. Another (newer) disk with a harder back is the one that is flying off. I've looked at the schematic and don't really see anything that would obviously cause the problem, nor is there anything obviously different in the speed or vibration of the machine. We are going to call the distributor (Glastar) and ask them (Crystallite couldn't help), but I wondered if anyone has experienced something similar or has some insight to offer.

Thanks.

Michele

[Morganica]

Have the discs become demagnetized? You might want to check to see how well they're sticking. Then I'd look at what's on both disc and the turntable--if there's rust or pits that could interfere, particularly if the disc is too rigid to accommodate.

[Jeff Wright]

might too much water be getting under the disc. Even if magnetic-backed, I've seen cases where too much water on the head will prevent the disc from firmly seating. Then the spinning forces (never sure which one any longer) throw the disc.

I would check, as Cynthia stated, the cleanliness of the head and the disc, the magnetization of the disc, and then the water.

[Dolores]

I had this problem with some of the new discs I purchased through Rio Grande. It was definitely water creeping under the disc. I solved it by; 1) Ever so slightly bending the disc in the middle so it sat absolutely flush (hold with fingertips around he outer edge and push very gently in the middle with thumbs, and 2) roughing up the magnetic pad on the back of the disc with a file so there was more traction to the wheel.

DOLORES