Understanding DVD/DVD-R Problems

[charlie_ps2]

Success with DVD/DVD-R on the PS2 is, first and foremost, a question of reflectivity and the causes of poor reflectivity.

The exception is (my thanks to Phreaker47 on ISONews for this) a game like GTA3 that is coded to stream data on the fly. Phreaker47 wrote " ...especially when you are driving through the cities... parts of the landscape that are just beyond the horizon are loading without interrupting the action. So, the effects of quality difference in DVD-R medias are exposed here. If there's a "hiccup" in GTA3, you're screwed because you need that data loaded right away or it will interrupt your game.. hence, the screen freezing with the message 'Error Reading GTA3 DVD', and the other effect being messed up textures that failed to load properly in this short time window". The v5s are faster PS2s and the effect is far less marked on those models.

Sony calibrate their CD and DVD laser diodes at around 1200 ohms, Dealing just with the DVD laser diode, this means if it can deliver 2mW (I think that's the value) power to the red laser beam, then a DVD (or DVD-R) with reflectivity in the range 45% to 85% will be read and processed by the firmware. Indeed a new PS2 laser can resolve Princo DVD-Rs (see below) which have reflectivity below 45%.

If the laser can't deliver the correct power, like it's near fried, worn out or whatever, then it will only read a DVD (or DVD-R) if there is sufficient power to read a disk with reflectivity higher up the band range. At worst, it will appear to emit light, but at a power lower than can generate a properly reflected return beam.

DVD-Rs have reflectivity in the range (my estimate) 15% to 65% and this is price related. I haven't been able to measure nor discover the reflectivity of Princos, but I estimate below 40%. But I know that Mitsui are 50% and Verbatims around 60%.

So now that you can see what makes a DVD drive sensitive, let's look further under the PS2 hood.

The Laser - does it wear out?
The" Laser" means the Laser Diode, the semiconductor that lases to produce coherent light. This diode is a sandgrain in size reaching 70 deg Centigrade. A very small increase in current (like pushed through by 5v or by over-reducing the resistance using the recalibration pots) will take the temperature through the breakdown barrier so that it lases dark light or weakly lases at the right wavelength. So yes, like a light bulb, the Laser will eventually wear out according to use.

Does a DVD-R wear the laser out?
A cheapish DVD-R has about/less than half the reflectivity of a pressed DVD and the laser power required to avoid re-reads is higher on poor media, achieved by re-calibration. A more expensive DVD-R (e.g. Verbatim) has about 60% ideal reflectivity which, with a clean lens, is sufficient to work with the standard laser power, esp. on a v5. So the laser will wear out sooner if you re-calibrate it and even sooner if you over-calibrate (by more than, say, 10%).

Red Screen of Death
When the disk is inserted, you can hear something akin to a mouse squeaking very rapidly. That's the lens moving up and down to focus and side-to-side to locate the groove that it follows to obtain the data. This lens movement is activated by magneto through tiny wires, current and magnets. Then the sled traverses the disk to measure its diameter (there are mini sized audio CDs).

When focusing, it tries first in red light; if there is reflectivity, the disk is a DVD/DVD-R and it can boot; if it is not a PS2 disk, the red screen appears.

If there is no reflectivity, it tries infra-red light and if there is then reflectivity, the disk is a CD/CD-R; if it is not a PS2 disk, the red screen appears.

If there is still no reflectivity, it goes to the browser. Either the lens is dirty or the laser cannot muster enough power and needs recalibration and eventual replacement.

There is an outside chance that the laser needs adjusting for the lens being parallel to the disk (azimuth) or the sled being parallel (the white cog).

So - there it all is. When you get the same question over again, then point to this thread. maybe the mods will sticky this.

[charlie_ps2]

Needs putting up to the top again!

[BG]

Can the moderator please make this a sticky???? Very useful info... Thanks Charlie.....

[charlie_ps2]

What mods?

I'm about to make another technical post on an allied subject.

[argo]

Hello Charlie,
it seems then that it would be a good idea to make sure the lens is kept clean, and if you avoid useing poor quallity media then your going to have the best chance of getting
a long life out of your laser.
What's the best method for cleaning the lens and how often should this be done?

THANKS THANKS THANKS.

Argo.

[charlie_ps2]

Just use a lens cleaning CD - the one with the brushes. Once a week except in Halifax and near the coal mines!

[dust2dust]

halifax air particle count is confirmed as being skyhigh
laser will require cleaning every minute

[argo]

Okay you two,
there's now't wrong with a bit of nutty slack
just don't mention the sheep and the wellies!!


Argo.

[charlie_ps2]

Originally posted by argo
Okay you two,
there's now't wrong with a bit of nutty slack
just don't mention the sheep and the wellies!!


Argo.

The only piece of nutty slack I knew in Halifax was a lady called Alice. You had to clean her little lens every hour or so!

[dust2dust]

hehe

[charlie_ps2]

Time to move this one up top again