Friday, January 28, 2011

Blue ray repair tips

I receive a lot of questions on how to diagnose failing blue ray drives.
It appears that questions are always the same ones!

I think it is now time to provide a small guide answering these questions so that everyone gets the once and for all !

Remind of the disc launch procedure :
1 - Present the disc to be inserted.
2 - The disc is automatically swallowed.
3 - Optical bloc is placed to the center if it is there already.
4 - Laser beam is activated to detect the disc.
5 - The lens does 3 4 up and down to focalise and detect the disc.
6 - If the disc is detected, rotation is launched to read content.
7 - Rotation speed evolves while reading the disc.
8 - Disc is ejected on demand with the eject button.
9 - Data are decrypted by the main processor and sent to the main board through the cable.

Now let's see what are the parts associated to these actions :
1 - Disc detection is done by the insertion sensor.

2 - Insertion is done by insertion motor. Insertion motor is driven by the BD7956FS chip on the daughter board.

3 - Optical pickup moves are done by the sled motor. The sled motor is driven by the BD7956FS on the daughter board.

4 - Optical laser beam is generated by the laser diode of the optical pickup. To produce the beam, the optical pickup needs power supplies generated on the daughter board.

5 - Focus is done by driving focus actuators. Focus actuators are driven by the BA5888FP on the daughter board.

Laser beam is concentrated with adjustable optical convergence parts. These parts are driven by the BD7956FS on the daughter board.

6 - Disc rotation is done by the rotation motor (SPINDLE). The rotation motor is driven by the BD7956FS on the daughter board.

7 - Disc reading needs a tracking servo. Tracking actuators are driven by the BA5888FP on the daughter board.

8 - Ejection is done by the insertion / ejection motor. The ejection motor is driven by the BD7956FS on the daughter board.

9 - Data transmission to the motherboard is done by the numerical heart of the daughter board using the 60 links ribbon.

Then what are the associated failures :

1 - When the disc is not automatically inserted, insertion sensor might be dead. Its red and black cables are very thin so they break easily, connector might also be not plugged properly.

You can insert manually the disc by pushing it a bit harder, it should be then swallowed.

2 - If the disc is not swallowed several parts can be dead.
The insertion / ejection motor. It can be tested individually by putting a battery to its connections.
The BD7956FS or the daughter board's power supplies are dead.

3 - If the sled doesn't move several parts can be dead.
The sled motor. It can be tested by manually pushing the optical pickup out to the border of the disc, it should go back to the center to detect the inserted disc.
The BD7956FS or the daughter board's power supplies are dead.

4 - The main blue ray drive failure problem is the laser diode dying. Failure can be straight, it means laser diode is dead, there is no beam at all, optical pickup must be replaced. But it can also be a power supply problem.

Failure can be more vicious ! The laser diode characteristics decrease with temperature rising, but optical drives provide temperature regulation compensations. But anyway, the laser beam power decreases in time. So an optical pickup might have to be replaced even with a beam available, but too weak. And finally there is the case where the beam power is not strong enough on a PS3 ant it is on another one ! This due to parts' characteristics tolerances that are not the same from one to another PS3.

As the laser diode generates the 3 beams CD/DVD/BR, there might be a way to check which of the optical pickup or the the board is failing.
If only the blue ray reading is failing and CD and DVD are read, we can conclude that laser diode is breaking because driving parts are 90% common for the 3 beams.

If several beams are having reading troubles we can say that the board has a problem because the probability having two beams failing simultaneously is weak.

5 - A focus or convergence failure will be difficult to identify. The disc will probably not be detected, or if it is, reading will be chaotic and will stop.

6 - Rotation might not appear for two reasons :
Either the disc identification is not correct, disc will not be read.
Either there is a failure.
The can be seen when the optical pickup is at then disc center, when laser beam is on and permanent. On should see a laser point on top of the disc surface. Actually, the disc detection is correct, the laser tries to read the disc but the disc doesn't spin.
Either the rotation motor is dead or the board has a problem.

7 - A tracking failure is hard to identify. I didn't see any ! Check the BA5888FP and the daughter board power supplies.

8 - If the disc is not ejected several parts can be dead.
The insertion / ejection motor. It can be tested individually by putting a battery to its connections.
The BD7956FS or the daughter board's power supplies are dead.

9 - A problem with the drive is that sometimes it is not seen by the PS3.
Main reasons are a broken connector on the main board (replace it), cable is broken or daughter board is not the original. For now I don't have a methode to make the identify the difference. Finally, if the daughter board is dead (power supplies or other) the drive won't be seen too.

Global checks :

In a general way, a method to identify if a part is failing it is to try another one, or try it in another working drive.

In the case where the BD7956FS or the board's power supplies are dead. It is not easy to identify, but a good lead would be to say that if the drive is seen by the PS3 then it is rather the BD7956FS, whereas it is not the case, it's rather the board's power supplies.

Obviously don't forget to check cables, the state of their pins and that they are properly inserted in the connectors.

Famous failures :

* Tac tac tac tac after reassembly.

(For better understanding take a look to article "Blue Ray drive explained : mechanical mechanisms" )

The tac tac tac problem is the following. When the left lateral part is in the "bottom" position when it shouldn't, upon the next start there will be another insertion process, so the pinions running on the rack at the bottom of the left lateral part will try to place it to the bottom position whereas it is already there! The tac tac tac corresponds to the pinion's teeth jumping on the rack's teeth because it can't move further.

The solution is to get the drive in its initial position. This means sled down, left lateral in "up" position, right lateral in "bottom" position. It initializes in a way the mechanical positions.

Most of the time when the left lateral part doesn't get back to its up initial position is due to the V part at the back of the drive that has its lugs out of its location in the left lateral part.

To solve the problem :

- Force the left lateral part to be in its "up" position. For this you will really have to go strongly on it ! It is a little bit baffling, but when I do it I get a big noise, as the teeth of the parts will pass on each other.
- Once the left lateral is up, check that the lugs of the V part are well placed. For that, check that when moving up and down the right lateral part, well the left lateral part follows the moves. Be careful that the initial position of the left lateral part is that teeth are not engaged i s the rack.
- Reassembly the drive, check that the upper cover gets in place easily.
- Restart the PS3, the drive should be mechanically re initialzed and should work properly.

1 comment:

  1. i have 2 ps3 drives with bdm-003. i put disk and it spins but theres no clock spin in the upper right corner of screen.

    when i put whatever disk in a ps3, clock spins in that corner even if isnt a ps3 disk but with those 2 ps3 it dont show that.

    i buy 3 new laser lens and put in those ps3 with no lucky.

    there is only 2 labeled fuses in the board and theyre great. i think there are more but i dont know where.

    do you have some recomendation?, i can put the 2 controllers because theyre cheap.

    thankyou for your time.