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Sony DVP-FX720 "NO DISC"

 
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mkgtm



Joined: 17 Apr 2010
Posts: 4

PostPosted: Sat Apr 17, 2010 6:18 pm    Post subject: Sony DVP-FX720 "NO DISC" Reply with quote

Hi!,

I'm having problems with my portable dvd Sony DVP-FX720. It shows "NO DISC" always. I would like to check what's failing...
Here is the service manual for the equipment:

http://www.eserviceinfo.com/download...DVP-FX720.html

The linear motor seems ok: when I press SW18, it moves until their initial position (at the center). The optical unit moves down & up two times, trying to recognize disc, and then LCD shows "NO DISC".

The spindle motor never tries to rotate.

I would like to know if the problem is in the optical unit or in the spindle motor. Following troubleshooting instructions for RF/Servo circuit, I checked the RF connection between HA1 and MT1389, and I think it's OK. But I don't know how to "check the related circuit on MT1389
RFL signal".

Can anyone help me???

Thank you very much!!
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sun Apr 18, 2010 5:07 am    Post subject: Reply with quote

Do you see any illumination of the pickup lens? Do not look very close but you should be able to see some sort of a tiny red beam illuminating along with the lens moving up/down. Also if I remember correctly, there should be a brief spindle kick.

For checking the spindle, you could always undo the spindle's ribbon and apply external dc and see if rotates. As far as t-shooting around MT1389, it is not easy without proper jigs and more likely OK.
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mkgtm



Joined: 17 Apr 2010
Posts: 4

PostPosted: Sun Apr 18, 2010 7:44 am    Post subject: Reply with quote

Hi vtech,

"Do you see any illumination of the pickup lens? "
No, I don't see any ilumination

"Also if I remember correctly, there should be a brief spindle kick."
No, I'm sorry, I'm not able to detect any spindle kick

"For checking the spindle, you could always undo the spindle's ribbon and apply external dc and see if rotates. "
I think you are suggesting to put dc on HA2. Is correct? or in HA4? I tried to remove and re-insert HA2 (and HA1) yet. No changes.

Thank you, seem that you know a lot about this equipment.
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sun Apr 18, 2010 4:53 pm    Post subject: Reply with quote

On closer look, obviously the spindle is of a different type that I originally thought. (Hall effect/servo type vs brush type). So the idea of applying DC is not valid in this case. Also, servo type motors rarely fail.
Btw, I forgot to ask the first thing; does it read a CD disc? & lens is not covered up with dust or anything?
If it does read a cd, more than 95 percent of the time it is the failure of the laser pick-up. (in this case you'd replace it as an assembly; spindle & all #4 in the exploded view)

I would have to say that if you can not see any laser emission, it still is likely that the laser has failed inside the pickup--barring any connection issues. As far as connection goes, just make sure that the HA1 & HA2 (& PUH5Volt--if possible to get at) along with the ribbons are solid and if so, rather than getting any more involved, your next logical step is to try another laser mechanism(if it is worthed?)
I used to be much involved in repairing various units when it was very economical in doing so in the USA. Not quite sure how it is in another countries or the situation of spares.
Here is a quick run-down of what suppose to happen;
In general, a turn-on signal is sent to the pickup when the lid down switch is activated. As the lase turns on, it is focused on the surface of the disc which automatically detects the type (DVD vs CD) and sends back a focus-OK signal. This in turn, send a command to the spindle motor as the table of content is instantly read and displayed. Then the unit waits for the next play command. All of this happens very quickly and almost always two lase diodes involved in a single package that are marked as LD_Cd & LD_DVD.
This is why you'd always want to try either disc when "no read" is encountered as a means of trouble shooting.
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mkgtm



Joined: 17 Apr 2010
Posts: 4

PostPosted: Mon Apr 19, 2010 8:07 pm    Post subject: Reply with quote

Thanks!!
I'll try to check what you suggest... although I start to think that repairing the equipment will be dificult!!
Thank you for your help
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mkgtm



Joined: 17 Apr 2010
Posts: 4

PostPosted: Sat May 01, 2010 4:08 pm    Post subject: Video through USB? Reply with quote

Hello,

Definitly, I cannot check what is happening with optical circuits, and I don't have another optical unit to be used as a test.

Maybe, a solution could be using the USB interface to read video from an USB storage device, but this DVD seems that only reads photos & music. Do you think is possible to upgrade the firmware to use USB port to read video?

Thank you very much for all your help!
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sun May 02, 2010 1:17 am    Post subject: Reply with quote

I have no idea but I seriously doubt the existence of such software upgrade for a DVD player! You would have to have major hardware modification alone.
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jman2k
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PostPosted: Tue Mar 08, 2011 1:45 pm    Post subject: region unlock Reply with quote

vtech wrote:
I have no idea but I seriously doubt the existence of such software upgrade for a DVD player! You would have to have major hardware modification alone.


what about a region unlock hack for this player?
any ideas?
can't seem to find anything on the net

thanks in advance
j.
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