DVDR990 - TZA1032

CD/DVD reading problems are often caused by a weak or dirty laser diode. Simply replacing it might be enough to fix the problem.

Thank you for response.

Why not suffice clean up this diode ?

I fear wherther afterwards i insert this diode on properly angle, identical as original.

The high spin rate of a DVD usually causes enough air movement over the laser to keep it free of dust.

On Fri, 07 Dec 2007 16:40:02 +0100, p put finger to keyboard and composed:

There appear to be two feedback components that are involved in automatic laser power control. One is the feedback diode in the pickup which directly senses the laser output intensity, the other is a photodetector which senses the reflected light intensity from the disc surface. Maybe you could fool the TZA1032 into believing that the laser output is low by adding a high value resistor (several megohms ???) between the FS input and ground? This should divert some of the sense current away from the FS input. I'd be very careful that you don't choose a resistance that is too low, as this may cause the laser to be overdriven. I expect you could monitor the laser power at the LASP pin, via an op-amp buffer. Having said the above, it seems to me that if the laser intensity is below spec, then the controller must already be driving it to the maximum. AFAICS, that's what automatic power control is designed to do.

Here is the datasheet for the TZA1032 laser driver and controller circuit:

- Franc Zabkar

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On Fri, 7 Dec 2007 09:07:00 -0800, "William Sommerwerck" put finger to keyboard and composed:

Here in Australia, Philips only supply the complete loader assembly, for between AU$200 and AU$300:

- Franc Zabkar

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Thank you for response. I can't localize connect point for this resistor - FS input. I look for 3,3 ohm resistor - is lack. In most be a capacitors. In rear of laser diode is 10 solder points:

• * *

• *

• *

• * *

To this come foil strip with 10 track, one is more width. I don't know, which from their is this needed (--> FS input). In datasheet for TZA not to be information, how, by i2c, enlarge max. reading laser current. i2c descrition in TZA datasheet is poor.

Pawel

I don't know whether be there TZA1032. Be IC:

0248 K2B242 T1030U3

Besides this, is strange, transparent IC with 10 pins, without name.

On Sat, 08 Dec 2007 19:31:57 +0100, p put finger to keyboard and composed:

Sorry, I have no idea, except that "0248" looks like a YYWW date code.

- Franc Zabkar

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I try disconnect laser and measure ohmmeter. I try light laser and identify feedbak diode. Supposedly laser diode be electrostatic sensible. It's truth ?

On Sun, 09 Dec 2007 09:22:15 +0100, p put finger to keyboard and composed:

I believe so. Replacement optical pickups are shipped with a blob of solder for ESD protection.

- Franc Zabkar

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I find TZA1032, DVD laser and FS diode. I think, that FS diode don't be a meaning in DVD reading:

I measere FS diode current in function to electric power supply to DVD laser.

FS diode current - electrical power for DVD laser:

1700 nA - 100 mW (it's maybe 10...20 mW light power - write) 3 nA - 5,4 mW (it's maybe 0,54...1,08 mW light power - reading)

This characteristics is very non-linear. I think, that 3nA current is to low for measure this and noise margin maybe is to low ~0dB (?). This require 400 mega-ohm resistor from FS input to ground. I don't know whether I correctly think ?

Pawel

On Sun, 09 Dec 2007 23:03:32 +0100, p put finger to keyboard and composed:

According to page 16 of the TZA1032 datasheet, the voltage on the FS pin is a steady 1.225V and the typical input current is 1000uA. AFAICS, a 12K resistor shunting the FS pin to ground should divert about 100uA of diode current, resulting in a laser current of 1100uA, ie an increase of 10%. I'd get the opinions of others before trying something like this, though. I'd also monitor the LASP current source pin (with an op-amp buffer if necessary) to determine the present condition of the laser.

- Franc Zabkar

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On Wed, 12 Dec 2007 08:11:56 +1100, Franc Zabkar put finger to keyboard and composed:

Sorry, that should read "resulting in a diode current of 1100uA".

- Franc Zabkar

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