how to repair dvd player

How To Troubleshoot And Repair DVD With The Symptom Of "No Disc"

For those who have been doing some repairs on DVDs will agree with me that ‘no disc’ symptom is a common failure mode in DVD/CD/VCD players. In this article I am going to take you through on how to troubleshoot and repair this kind of fault. BUT FIRST A BRIEF OVERVIEW OF A DVD PLAYER: When you open a DVD player you find that they have a lot of similarities in design between different models with very little variation between different models almost to the point of component level.

Therefore if a technician understands one model pretty well then you will have no problem when a customer brings a different model to you shop.

Basically all DVDs have three main modules (units) which work together in harmony as shown in the figure below.

dvd schematic diagram

We have the Power Board which is usually S.M.P.S but in old ones they used to have special types of transformer with many output to supply the power to the other circuit.

Next you have the Loader which houses the Pickup and then the Decoder (electronics board) all interconnected by use of wires (conductors) or ribbon connectors.

dvd loader

So let assume you have received a DVD from a customer with the No Disc error, first before opening up do some initial test. Open the drawer and load a Music Disc which you are sure it is not scratched or defective…if the DVD open and closes the door fully then we can conclude that the doors are okay.

Then listen above the loader for the sound of disc spinning, the way the disc spins can tell you a lot if the spinning is healthy or not. The disc should spins smoothly at around 500 RPM if everything is okay.

Now open up the machine and go to the pickup, if the pickup is on the inner area push it slowly and carefully to the outer zone with power off.

dvd tray

Now power on the DVD and observe the pickup and the Lens. For safety precaution don’t look at the lens directly with your eyes, just look at an angle from a distance.

If the pickup moves to the inner area smoothly and after reaching the inner lane the lens start moving up and down emitting red light then most probably the lens is okay.

If the disc is spinning slowly expect the spindle motor is probably shorted or the power supply to the spindle motor has some problem

To test the spindle motor with a DMM, set your meter to low resistance test (200 ohm) range, if it is okay should read between 5 and 20 ohms.

dvd spindle motor

On analogue meter, this is my favorite set the meter to X1 and measure across the two wires coming from the motor(red and black) if the motor is okay, it will spins at very high speed indicating to you that it is up to the task.

If the spindle motor is healthy then follow the supply for this motor to the decoder(motherboard) looking for the filter capacitor for that line, usually 470uF/10v, this capacitor has a high failure rate and should be tested with ESR meter or directly replace it. If you find this capacitor has swollen top just replace it with the same value capacitor but high voltage rating (470uF/16V) is okay.

dvd player repair

Sometimes also a no disc symptoms can be caused by disc table (spindle platter) height set too low or too high. If you spin the disc with your hand it should rotate freely.

dvd player troubleshooting

In conclusion most of DVD problems are mechanical and very inexpensive to repair and doesn’t require sophisticated machinery to test just observation using the best tools I have come to realize in my troubleshooting experience which are absolutely free, YOUR SET OF EYES.

A word of advice- I have found several of these spindle motors which are not working right from the shop and therefore I advise you to test on the counter before taking it home only to realize that it’s not working. This is also true with other components make it a routine to test components before replacing them in circuit.

Thank you guys

Wish you all the best,

Humphrey Kimathi

========================

Here are few questions i posted to Humphrey:

1) Jestine Yong- Where can the repairer get the spindle motor?

Humphrey- Here in Kenya they are found almost in every electronics shop, for other countries i would not know.

2) Jestine Yong- Generally how much is a spindle motor cost?

Humphrey- I buy them at Kenya shilling 80/- same as 1 USA Dollar

3) Jestine Yong- Is all spindle motors are the same?

Humphrey- I have been using them on most types on DVDs found here in the market, sony. LG, Jvc, and many others so i would say the are the same, but be sure the working voltage is the same(usually 5.9v) and also the size.

4) Jestine Yong- Could i use spindle motor from one dvd to replace on the other?

Humphrey- Sure: if tested and found to be okay.

I hope you like this article and answers by Humphrey Kimathi and if you wish to visit his blog you can log on to http://humphreykimathi.blogspot.com/

Click Here to Get 24 Best Electronics Repair Articles

Click here to learn how you can become a Professional in Switch Mode Power Supply Repair

Click here to learn how you can become a Professional in Testing Electronic Components

Click here to learn how you can become a Professional in LCD Monitor Repair

Click here to learn how you can find burnt resistor value

Recommendation: