Philips 28PT44060 (L01) - Pincushion issue

[Alex KL-1]

Originally Posted by Claustrofob

Yesterday I made some good progress!
I read more about the "How to change an Option Byte" in the service manual and then I compared what this model should have. Turns out, they were wrong!

Current Options Byte parameters
OP1 - 4
OP2 - 196
OP3 - 0
OP4 - 8
OP5 - 240
OP6 - 0
OP7 - 67

What the 28PT44060/01 model should have:
OP1 - 4
OP2 - 196
OP3 - 224
OP4 - 40
OP5 - 228
OP6 - 0
OP7 - 67

... and voilá! I now have the EW parameters available.
I guess this is a method to enable features that comes with the model/type of chassie in each model?

Anyway, this means that somehow/someone must have accidently changed these parameters when fiddling around in the service menu. I know I didn't!
I can now expand the picture and reduce the pincushion and finally adjust to a good looking geometry!

Super thanks to @Alex KL-1 for all your support and help! The part where you mentioned that 7200 was controlled from the TDA95XX, that was the moment I started to read more about the Option Bytes.
Thank you for that!

Great! I'm happy that you can now enjoy the TV at it's full features (problem solved)!

Yes, some people have the talent for accidentally accessing the menus. I testified some like your TV here (wrong parameter or model), and some in "Hotel Mode" by accident...
Also, some curious people without any knowledge in this area that gets the menu codes...
EDIT: is very rare, but some can corrupt the EEPROM when a strong ESD occurs at power off moment.

[Alex KL-1]

Originally Posted by Alex KL-1

.........

Yes, some people have the talent for accidentally accessing the menus. I testified some like your TV here (wrong parameter or model), and some in "Hotel Mode" by accident...
Also, some curious people without any knowledge in this area that gets the menu codes...
EDIT: is very rare, but some can corrupt the EEPROM when a strong ESD occurs at power off moment.

...but in fact I even misssed that, and not associated to your TV issue at first glance. Most models I'm used to fix hiddens the parameters for different models.

[Claustrofob]

Originally Posted by Alex KL-1

...but in fact I even misssed that, and not associated to your TV issue at first glance. Most models I'm used to fix hiddens the parameters for different models.

Is it possible for the TDA95XX to loose these settings since the EW transistor had failed?

[Alex KL-1]

I believe the replacement MOSFET have a different Vgs(th) and perhaps some difference in gain (gm), shifting the set points needed (correction), so this grants a adjustment.