Philips 42PFE0001D/H - distorted colors - defect AS15F chip on TCON board

Another AS15 repair :-) I was interested in this Philips TV, because it once was the absolute High-End. It has an external box with the power supply and main board. Two cables go the monitor, which contains the logic board, TCON and inverter.

The seller liked it so much that he offered to buy it back if I managed to fix it. Fair deal.

Switched it on and got this:

Really bad color distortion. The Menu titles even disappeared sometimes into the dark. A typical AS15 gamma chip fault.

Not much in the monitor:

Funny idea: a heat conducting block for a back cover made of plastic. Well, it worked for 7 years, so it wasn't that stupid, I suppose.

And here it is. The blue TCON board of doom made by AUO. The chip is on the upper right.

Time for gamma measurements. In brackets are the values of the new chip. Three test points were far off.

vgama1: 15V (15.5V)
vgama2: 14.7V (15.4V)
vgama3: 10.5V (10.8V)
vgama4: 10V (10V)
vgama5: 9.7V (9.8V)
vgama6: 7.7V (7.7V)
vgama7: 7.7V (7.7V)
vgama8: 7V (6.9V)
vgama9: 7V (6.9V)
vgama10: 9.2V (5V)
vgama11: 5.8V (4.7V)
vgama12: 10.7V(4.0V)
vgama13: 0.43V (0.36V)
vgama14: 0.38V (0.33V)

As always the heat conducting block stuck to the chip and broke off. I think we have a pattern here. It looks as if the material had disintegrated. Maybe that sealed the death by heat of those chips.

To solder the chip I used my new horseshoe solder tip and it worked fantastic. Much better than the spade type I had used before.

That's much better!

Perfect grades of black:

Being curious I peeked into the so-called hub, the control unit. I couldn't figure out how to get to the power supply below the main board. The chassis would not come out and I decided not to mess around with stuff that works. I just blew out the dust from the cooling fan on the left.

Hallo Frau Johansson!