Wentai DVD Player Repaired
This DVD Player brand WENTAI Model: DVD-3031, China made was brought to me from a co-worker because it was fully dead.
First thing was to disarm it.
And check the Power Supply Unit voltages.
As you can see in the photos above there was AC mains (110 volts in my country) and there was voltage-out in the Power Supply Unit (5 volts in this case).
This means the power supply was good! Anyway the PSU was extracted and checked to look for any cold solder joint, bad e-cap, etc.
Everything was ok, so the search had to be continue in the mainboard. In this mainboard I found two leaky semiconductor diodes (1N4004: Plastic Silicon Rectifier).
The diodes used for substitute the bad ones were 1N4007 (recovered from another PCB).
They were soldered back to the mainboard and when the appliance was turned On, look at the result in the photos below.
Wow! The DVD Player really turned On perfectly and the owner was very happy.
This article was prepared for you by Humberto Rodriguez, one of our ‘Master Authors’ from Cuba.
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Gary Gemmell
May 12, 2015 at 9:26 am
Simple fixes always the best - for time and money!!!
lol
Good work Umberto i always enjoy reading your work.
Gary
Humberto
May 12, 2015 at 11:18 pm
Thanks Robert
Humberto
May 12, 2015 at 11:22 pm
Sorry, thanks Gary Gemmell
Robert Calk
May 12, 2015 at 9:31 am
Good job, Humberto.
Humberto
May 12, 2015 at 11:26 pm
Ok Robert, you are welcome
Peter O
May 12, 2015 at 10:12 am
I know this is probably a dumb question but .....
Did you suspect the diodes for some specific reason?
Did you remove other CB components for checking?
What exactly is a leaky diode, do you mean it has near zero resistance in each direction? Maybe you used a diode checker?
Anyway I was pleased to see got a good result apparently quite quickly.
Humberto
May 12, 2015 at 11:32 pm
Well Peter O, first thing done was to test on the PSU, and due to it was in perfect conditions I suspected of this pair of diodes, because it's a common malfunction of this kind of DVD Player (when they are in bad conditions the Unit will not start). If these diodes are changed for similar and good quality ones, you'll never have this trouble again. A Handheld Digital Multimeter was used to check the diodes, the same that appears in the photos.
Chris
May 12, 2015 at 4:16 pm
Good work humberto, i like reading you articles.
My best regard.
Humberto
May 12, 2015 at 11:51 pm
Thanks Chris, my best regards for you too.
Paris Azis
May 12, 2015 at 6:48 pm
Good work Humberto!
Regards
Humberto
May 12, 2015 at 11:52 pm
Thanks Paris, UR welcome
Neto
May 14, 2015 at 12:18 am
Hi Humberto,
It's not clear what pair of diodes you refer as common faults on the main board...
Please specify their position or function on the schematic.
Tito Kanshulu
May 14, 2015 at 2:06 am
Good work Humberto,we have added this to our knowledge.
Yogesh Panchal
May 14, 2015 at 3:18 pm
Good work Humberto thanks for sharing.
reza
May 15, 2015 at 11:27 pm
hi dear Humberto
thank u.
Lee
May 19, 2015 at 10:39 pm
Hi Humberto,
Are these diodes acting as input bridge rectifier?
If yes, I cannot see how 5V output voltage can be present?
Maybe the fact they were "leaking" is why they still do the job but the 5V does not provide enough current to push the unit...
Thanks and keep up the good work.
Robert Calk
May 21, 2015 at 2:36 am
It is also better to use an analog meter with X10K that has the 9V battery in it to check diodes, rather than a DMM.
Taring K Arioka
May 22, 2015 at 5:41 pm
Thank you for sharing this good article.
Orlando
June 7, 2015 at 11:34 pm
Nice articule.
Litlle things,great work.
It makes our work fun and wonderful.
Anuradha
August 25, 2015 at 11:47 pm
I have a DVD player that says no disk. When I closed the tray the laser went on for a second and spindle motor rotates a bit, then nothing and no disk message. I have cleaned the lens with cleaner but nothing went good. The ribbon cable was perfectly fine. What could be the problem do it have?
edgar
December 11, 2016 at 11:16 am
can i ask what number of 6pin IC in the picture?thanks