Tuesday, September 14, 2010

No disc symptoms- JVC DVD

No disc symptoms- JVC DVD

No disc problems in all types of DVD is a common phenomenon, before a DVD start reading the disc, there are several test it does just like the booting of the computer (cpu) called start up process.

If by any chance any of the stage is not working the DVD will display an error on the screen, most of the time it is disc error, no disc etc.

Among the components which are first suspected is the LENS but from my experience this is one of the most stable component with a relatively very low failure rate.

Top suspect is the Spindle motor (the motor that spins the disc), over 75% no disc error is caused by this small motor where the disc sit on.



How to measure 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.

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.

A word of advice- I have found several of these motors which are not working right from the shop and therefore I advise you to ask the store keeper to give you the meter and 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.

Back to my dead JVC DVD

As usual my first suspect- Spindle motor. Measuring this motor, YES it was dead short.

I replaced with a new one, alas still no change..Still no disc symptoms.

Looking at the logic circuit (motherboard) I noticed a swollen cap on +5 volt line. A good hint what might be pulling the spindle motor power supply down!

I replaced the capacitor (470uf/10v) with 470uf/16v…still no change but this time I noticed that the lens reader is trying to focus, I mean moving up and down.

But as the lens move up I noticed it is hitting the spindle motor table when trying to focus.

Another clue, that the disc table (spindle platter) is not adjusted properly, meaning when I replaced the spindle motor I failed to set the high correctly.

Hence no disc error. I adjusted the spindle motor table up slightly and the DVD came back to life.

BIG PROBLEM --- SMALL SOLUTION

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.


Thank you guys..


Let met in the next class

9 comments:

  1. No Kimathi you are wrong. 99% of the "No disc" problem is due to lense.

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  2. thanks for your comment...lets hear from other technicians....my fellow techs out there what is your take on that?

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  3. hello

    yes i had same problem as you told with bad new
    motor one time
    tnx
    beh

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  4. Humphrey
    How do you find a spindle motor to match the one in your drive ? I suppose they are not all the same ?
    Our shops don't carry motors, only way is to scavenge one from an older drive.

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  5. Most of DVDs here are imported from china. mostly sony, LGs, Jvc etc and interesting this spindle motor is same. send me pic of the one you have a problme i try to figure out the way out.

    regards Humphrey

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  6. Ever have a JVC XV-N50 (or any other) spin up a DVD fine (and play) but will not spin up a CD? What would cause that?

    Curious

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  7. Hi Curious..No. but i have seen the other way round. which require software upgrade.
    kind regards
    Humphrey

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  8. hi sir,

    first I seen your blog and caught me quiet interesting.,thanks for the hints you posted about No Disc error.
    actually I own and run now a small repair shop here in the Philippines, often I got to encounter
    lots of no disc error and you are true mostly the no disc error cause literally of the Spindle motor.

    now how about component system codec that has multiple cd tray that keeps on changing disc? what do you think would be the error with this kind? I got now few unit that gives me headache because I could not figure out whats wrong?

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  9. Hi win, i haven't come across this symptom..could be power supply is messed up?
    regards Humphrey

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