Storage

TechRepublic Tutorial: Don't throw out a bad CD-ROM drive until you've tried these techniques

Learn not to overlook things when troubleshooting hardware

CD-ROM drives tend to be one of the more durable components in a PC. Generally, when things go wrong with a CD-ROM drive, the problem tends to be related to the cables connecting it to the PC, the IDE controller, or the drive’s laser. If the CD-ROM drive on your PC goes out, you might be tempted to just replace it. After all, you can get a replacement CD-ROM drive for under $50. But before you go and shell out 50 bucks, there are a few simple techniques you can try to repair the drive.

Clean the laser
Most of the time, you don’t have to worry too much about lasers in CD-ROM drives on desktop PCs. On such drives, the laser is buried deep inside the drive. Unless the PC is located in a really dusty environment, the lasers don’t generally get dirty enough to cause problems. Furthermore, many of the newer CD-ROM drives have built-in lens-cleaning mechanisms.

But just because a laser is unlikely to cause the problem on a desktop PC, don’t automatically rule it out. I have seen 10 instances in the last five years of CD-ROM drives with dirty lasers. For desktop computers where the laser isn’t exposed, you can use a cleaning CD, which is simply a CD with small brushes attached. As the CD spins, the brushes clean the lens.

If you're a little braver, you can actually open the CD-ROM drive and clean the drive with a cotton swab or a can of compressed air. Be careful not to exert any force on the laser lens to avoid damaging the springs that support it. Also, realize that by opening the drive you are almost certainly voiding any warranty the drive may have. This should be a last resort.

Laptops are much more likely to have dirty laser lenses because often when you open the drive door, the lens is exposed (see Figure A).

Figure A


Check the cables
Once you've cleaned the drive’s lens, I recommend disassembling desktop PCs and checking all of the cables to make sure that they are connected tightly and are aligned correctly. Before you begin the disassembly, make sure that the drive’s power light illuminates and that the drive’s eject mechanism works correctly. If so, you can rule out the drive’s power cable as the source of the problem. Otherwise, the drive may not be getting any power, and the power cable is almost certainly the cause of the problem.

If you determine that the drive isn’t getting power, but the drive’s power cable is connected, look for an alternate power connector inside the PC. Sometimes the wires that attach the power connector to the power supply will come loose and cause the power cable to not work correctly.

If the drive is getting power, check the IDE cable, shown in Figure B. The IDE cable should be oriented so that the red stripe faces the power cable and lines up to pin 1 on the IDE controller.

Figure B


I also recommend making sure that the drive’s master/slave jumper (see Figure C) is positioned correctly. If the cables appear to be snug and correct, you might consider replacing the IDE cable with a known good cable. While doing so, pay attention to see if any pins on the controller are bent or missing.

Figure C


Try a different IDE controller
If the IDE cable appears to be attached correctly and the jumpers appear correct, try moving the IDE cable to the machine’s other IDE controller (see Figure D). If the drive works off the other controller, the problem is a bad IDE controller and not the CD-ROM drive.

Figure D


If the drive doesn’t work off either IDE controller, see if the drive is daisy-chained to another IDE device, because the other device could potentially be interfering with the drive. Try removing the other device temporarily so that the CD-ROM drive is the only device using the IDE controller. Before testing the drive, make sure that the drive’s jumper is set to Master, since it will be the only device on the controller. If the drive works then, the other device on the controller may be damaged or it may have an incorrect jumper setting.

Troubleshooting vs. replacement
Once you have checked the IDE controller, the IDE cable, the power cable, the jumpers, and the laser lens, you can be reasonably sure that the drive is bad. You can usually test these components in a matter of minutes. The biggest thing to remember is not to spend too much time diagnosing a CD-ROM drive. If a new drive costs $50, and you are paying a support tech $50 per hour, an hour spent diagnosing the problem could have bought you a new drive.
0 comments

Editor's Picks