Pioneer DVL-909 doesn't read discs

[abhi1981]

Hello,
Recently bought a cheap Pioneer DVL-909. Everything seems to be working properly EXCEPT that it would not read any CD or DVD  . Didn't test an LD as I don't have any.
After loading a CD, it will try to read it with both the lenses, but finally ejects the CD. The disc spins at low speed(for a short while) when the CD lens is reading and then it gives up and then comes the DVD lens. Same thing happens with the DVD lens, except that the disc spins faster. Ocassionaly the DVD lens will strike the surface of the CD, while focusing, causing a rattling noise.
Same thing happens with a DVD.
When no disc is present it says NO DISC.
Please help.

[Jeff eelcr]

Never worked on that model but the first ones made for ford had ribbon
cable to laser bad and or laser assy bad most times with that problem.
Jeff

[max-bit]

Probably a laser died ... which is a big problem, lasers are hard to get and which means expensive.
The laser is the VNP1497 model. Unfortunately, it's hard to buy a new one. (maybe they don't appear anymore, unless someone finds it in a drawer, by chance)

[abhi1981]

I can see the DVD lens glow red while its focusing and the CD lens also has a red dot while seen through camera. Probably the lasers have not died .

[David_AVD]

The term "laser is dead / bad" is referring to the laser assembly (tx, lens, rx, suspension), not just just the emitter.

Just because you can see some emission from the lens doesn't mean the output is too low, poorly focused or some other issue.

[abhi1981]

Totally agree with you.
But I don't understand one thing, how is the player able to differentiate between a DVD and CD?
The TV display shows the loading screen, and as soon as COMPACT DISC appears, the CD is ejected. Same with DVD.
Is this happeing because of a weak laser?? Then how come both the lasers are weak ?? 

[David_AVD]

Firmware on CD / DVD players varies a lot, so how it works out the disc and what it does varies.

Are there small surface mount electrolytic capacitors on the board that the laser plugs into? On old units they have often gone bad. Sometimes they will smell "fishy" or show a wet residue when you remove them from the board.

[abhi1981]

Yes, on the DVD board, there was some oily residue on the audio/video decode chip and the surrounding area, marked in red. The heat sink sponge was soaking with it. Didn't notice any fishy smell, but definitely "something is fishy"

[David_AVD]

Next step might be to carefully replace those SMD electro caps. This fishy smell usually doesn't occur until you try and desolder the caps.

Twisting the cap bodies off (then desoldering the legs left) seems to be popular these days. I didn't believe it when I first saw it, but it does seem to work. Maybe watch a video or two on it and/or experiment with a scrap board first.

[abhi1981]

Yeah, I watched that video too. Mr. Carlson is a legend. Anyway, i'll check those caps.

[max-bit]

Just because the laser is shining does not mean it is working properly.
The laser diodes lose their ability to work as a laser over time.
Later, such a laser diode turns into an ordinary light diode.

What's worse, the newer laser diodes, the shorter their lifetime. The old LD IR from the 80s can work without problems until today, the ones from the end of the 90s are a few years old, the newest ones barely reach the "warranty"

You also have SMD electrolytic capacitors, it is worth checking their condition, they liked to pour out. It is worth desoldering a few pieces to check if they have any signs of damage and their parameters.

[abhi1981]

There are a couple of 100uF 6.3v caps . Can I replace them with 25v or 16v ones? 6.3v is not available.
Please advise.

[Haenk]

higher voltage is fine, as long as the footprint matches the original...

[edpalmer42]

Did you try cleaning the lens?  I use a cotton swab dipped in isopropyl alcohol.  That's always the first thing I try because it's so easy.

[abhi1981]

Yeah, that's the fist thing I did. Cleaned the lens and the infrared sensor, lubricated the gears, but nothing happened.
Maybe a PCB or alignment problem.

[abhi1981]

Just noticed that the body of the player has 220v AC on it. I can feel a mild electric shock, just a little vibration if the body is touched lightly. The line tester also glows, and more brightly if I'm barefooted. If I reverse the polarity of the power plug, then the current disappears. It also disappears if I connect the body to earth.
I have noticed that this happens will all equipments having SMPS.

This happens with PC cabinets too. But PCs have ground connections, so no problem.
Why don't audio equipments have ground terminals?? Can this current damage the equipment??

[abhi1981]

Finally got my first ever lot of 40 Laserdiscs.
And the player is playing them . But, it still wont play DVDs and CDs.
After playing side A for about 2 min, it starts looping for 3-4 sec and to move forward I have to skip to the next chapter. The same thing happens again and it becomes harder to skip. Same problem with side B too. While looping, it makes a rattling noise, but I cannot find its source. The gear is OK and while changing pickups, the gears work smoothly.
Someone's been into the player, a power supply K2333 mosfet has been changed and the fuse has been conveniently shorted with a wire 


One more thing, I connected the audio and video out to my amp and there was no video and audio, only noise. I reversed the power plug and the audio video was ok. I believe there is some sort of leakage current all over the player. I can feel a mild shock when I touch a bare metal part. This current was probably going into the amp and causing the noise. Could the power supply be faulty???

[abhi1981]

There are 2 safety film capacitors connected across the line and 3 ceramic capacitors connected across and to ground.  Another 3 after the rectifier.
Could they be causing the leakage??