I built my computer with two DVD Drives that I had reused from other other computers. This is handy because when I have digital media to read or write from a disc, there's normally more than one required, and because, short of Blu-ray, the drive speeds mostly haven't changed since 2007 or so. I could have added a third, but the motherboard does not have a second PATA channel to support it. Thus there is a third drive, probably the only one that was purchased alone, in a USB enclosure.
The two drives in the PC are
Samsung SM-348B CDRW/DVD
NEC DVD +/- RW ND-3450A
And the Drive in the enclosure is a
LiteOn DVD +/- RW -RAM DH-20A4P
On a recent audiobook transcription project, I found that both the Samsung SM-348B and the LiteOn DH-20A4P no longer wanted to open without mechanical assistance. Some investigation showed that depolymerization of rubber parts (where the rubber deforms and becomes sticky) was the culprit in both instances, though the problems were distinct for each device.
The Samsung has a foam rubber gasket around the front of the drive tray, presumably to keep dust from getting into the mechanism. When the drive ejects, this seal was getting caught on the front bezel of the drive as the tray tried to slide out, blocking it's path. I could help it eject the catching the tray with my fingernail as it pushed out a bit after I hit the eject button. The front part of the tray can be removed by gently lifting two tangs on the bottom and sliding it upward, allowing the gasket to be removed. Upon removal, the gasket was obviously deformed, smushed wide, and quite sticky, which was probably helping it latch on to keep the tray from opening. I trimmed the gasket with scissors and reversed it so the sticky part faced the front of the drive tray, yielding a non-sticky surface between the tray/bezel contact. There still some residual smudge on the drive tray, but it opens reliably now.
The LiteOn was more of a humdinger. Hitting the eject button yielded some small mechanical noises as the mechanism tried to open, but the tray didn't budge and it couldn't be coaxed to open by pulling. It required a strong assist by using a paper clip. I took the metal enclosure off the drive, yielding it's plastic frame and internals. There was nothing apparently wrong. Had I tested at this point, I would have found that it ejected smoothly in this state. However, I incorrectly assumed a lubrication issue and applied some thin silicone grease to all the sliding surfaces in the drive. After lubrication, I powered the drive and found the naked mechanism worked smoothly, concluding I had solved the problem, the drive was reassembled and put back on the PC, where it promptly refused to open, as before.
Several repeat inspections failed to find the problem. Testing showed that the drive would open when naked, but when the protective metal shell was in place, it would get stuck closed. I initially concluded that the rubber drive band, a square belt of about 25 mm diameter, between the motor and the tray gear train, was worn out. This part fails commonly enough that they can be purchased on Amazon. This seemed rational as I could see the spindle spinning under the belt when the drive was trying to open the tray. However, the belt was under good tension and everything looked OK. It also did not explain why the drive worked fine when the case was removed. The drive also ejected ok when the plastic frame was manually torqued in various ways, so it seemed unlikely that metal enclosure (which was in find shape) was distorting the drive mechanism.
A google search showed a post in the digitalFAQ forum where a user complained that they were having problems with a drive leaving "gunk" on the center of CDs, and suggested that the drive spindle was sticking to the bearing in the top of the drive when a CD was not present. It took a moment (meaning, several hours) for the implications of this to sink in for me. The drive ejects by lowering the drive spindle to allow a clear path for the tray to slide forward. When a disk is inserted, the spindle raises and presses the disk into a bearing on the top of the drive house. If there's not a disk present, and the spindle is sticky, it will adhere to the drive housing lid (aha!). When a disk is present, there's a few millimeters travel which gives the mechanism enough momentum to break free.
Thus, I resolved to "solve" the LiteOn problem by storing the drive with a blank CD-R inside of it. If it starts having problems with ejecting, I'll probably employ the talcum powder trick to dry the rubber surface.
