Tips and Hints For Diagnosing DVD/CD Combos and Players (Page 1 of 2)
Know the safety facts first
If you have no electronic experience or training, there really are no user serviceable parts inside the set. It's all solid state, and you’re going to need to know how to use a simple digital or analog multi-meter. Also, you should know how to solder, as well as unsolder, as almost all of the parts in most sets are soldered in place on the printed circuit board. When dealing with TV/DVD combos, there are also the safety issues concerning the HI Voltage found in TV sets. All TVs with a picture tube, including three tube projection sets, will have a HI Voltage transformer with a heavy red wire that runs up and connects to the picture tube with a suction cup. Under there is an average of 32,000 volts when the sets on, and even when the set is off, can hold a large electrical charge.
First things to check
The most important thing for a DVD/CD player is make sure the unit’s laser lens, or what some call the “eye”, is clean and free from any film or dirt. The best way to do this is to use a readily available, CD/DVD lens cleaning disc. I have found that 65% of people with a "broken" player could have saved themselves a trip to the repair shop if they would have used a cleaning disc. Of course, sometimes a cleaning disc can be hit or miss, as there are some players/recorders that won’t allow cleaning discs to work inside them. If this is so, or if the disc cleaner doesn’t work, there’s another step that involves taking the unit apart.
Getting into the unit
For this example, the unit is a TV/DVD combo. You just need to remember the safety facts mentioned above about working inside of a TV set, and IF you ever feel uncomfortable at any step of the way, STOP! Reassemble the unit and take it to a repair shop.
Lay down the TV combo unit face down on a soft surface. There should be screws holding down the back to the set. Remember to look around the back area around where the inputs are for any fasteners. Gently pull the back straight up, remembering that sometimes you may need to tap around the cabinet to loosen the back from the front cabinet.
Once the back has been removed, look around the bottom part of the chassis. Depending on the make and manufacturer, most DVD and VCR chassis are mounted on the bottom of the set. Examine the bottom of the set while it's lying down to see if there are any screws holding onto, or holding in, the DVD chassis assembly. Also, look all the way from the back toward the front to see if there are any screws holding in the chassis from the front of the unit. Be sure to check for wires and cables that may be attached to the DVD chassis and TV/power supply, as they will have wire ties on them. Sometimes these have to be clipped off, BUT always remember to tie them back out of the way when you’re ready to reassemble.
Once the DVD chassis is loose, sit the TV up so that it rests in a normal position. However, some sets cannot stand up when disassembled and will break the bottom of the cabinet if you try. So, if the cables are not long enough to slide the DVD chassis out, you're going to need someone to hold up the set until you can slide a block of wood inside the cabinet from the top to the bottom of the cabinet.
Gently slide out the DVD chassis, and make sure you’re not stretching any ribbon cables or wires. Some manufacturers will have a metal cover over the DVD chassis assembly, which is usually held on by two or four screws. Take the screws out and slide off the cover by lifting straight up, or slightly lifting the back part of the cover and sliding back while pulling at a slight angle. This is also how to remove most covers on regular DVD/CD players/recorders.
Manually cleaning the lens
To locate the laser lens, look around the door or drawer of the DVD player and you will see a small circular disc, which is often called the turntable or disc platter. Right off the edge of the platter you should see a small clear lens. There are some manufacturers that have had problems with the lens, depending on the age of the unit. In these problem players, moving the unit to a different location, turning the unit upside down, or sometimes even without moving the unit, the lens can become detached from the laser assembly and floats around inside the unit. You can re-glue it back with a little crazy glue, BUT it must be perfectly centered, and without getting any glue on it. So, if you don’t see the plastic lens, but instead see the laser pick-up assembly, look around for the lens inside the unit and glue it back on.
To clean the lens you must use very little pressure. Take a cotton swab and barely moisten it with plain, non-scented, or oily type alcohol. In a swirling motion, very gently rub the lens until you’ve covered it entirely. Then repeat using the dry end.
Now, if no cables are disconnected, and if you can verify nothing is touching the TV or DVD chassis, you can plug in the unit and check if this helped the player to "see" again. Most of the time you can check as is, though on the combo units you're going to have to slide the chassis assembly all the way back into the cabinet to get it to work because the cables are often too short. If this didn’t fix the problem, please read on.
Other things to check
If the cleaning didn’t help, don’t despair just yet. You can see if there’s a problem elsewhere in the unit by using a few simple tricks and tips.
First thing you want to see if the unit’s laser is in good working order. This method isn’t foolproof, but most of the time works admirably. When you insert a disc, see if you can look up underneath where the disc sits on the turntable. Observe the laser lens going up and down. If the lens is trying to focus, that’s good! After a few seconds of the lens trying to focus, the platter should start to spin. On almost every CD/DVD unit I've encountered, the unit won't spin unless the laser has properly focused on the surface of the disc.