Phillips 42pfl7432 no backlight

[ricosavy]

I replaced chip that was burned had a hole in it the pin where it mounts gone so I jumpered it to capacitor.when I test voltage on to transistors k4075 in middle pin I get 24 volts the side pins I get 1.4 volts.are these bad.

[ricosavy]

Re: Phillips 42pfl7432 no backlight

Here is a pic

[ricosavy]

Re: Phillips 42pfl7432 no backlight

Here another pic

[ricosavy]

Re: Phillips 42pfl7432 no backlight

Here is a pic of the chip before I replaced it

[PL519]

Re: Phillips 42pfl7432 no backlight

Hi,
this is the typical failure with these LG inverters. Did You do the modifications recommended by Philips? Just had this issue and could it solve it with the repair kit containing the BD9897, the TVS diodes, SMD resistors and MosFets.

[ricosavy]

Re: Phillips 42pfl7432 no backlight

ok i will try it

[ricosavy]

Re: Phillips 42pfl7432 no backlight

On the mods do you do both are do you do one and if you do one which on is the best one to do.

[budm]

Re: Phillips 42pfl7432 no backlight

You have to do Both of them.

[ricosavy]

Re: Phillips 42pfl7432 no backlight

I replaced the transistors and chip. Still back light did not work. I tested the transistors on master on top I get 24v on legs I get 1.4v on the slave transistors I get 24v on top and on legs I get 5.8 v.any ideas on what is causing my voltage to be low on transistor legs 1.4v. Also on master I see the blue light come on then dim out and turn off.

[ricosavy]

Re: Phillips 42pfl7432 no backlight

Does any one know the value of cap mc45 and diodes mzd2 and md5 on master inverter.any help would be appreciated I believe the diodes are shorted. Thanks

[ricosavy]

Re: Phillips 42pfl7432 no backlight

Well I replaced the Zener diode mzd2 which was bad I replaced it with a 5.6 Zener diode which had the e2 marking and the tv is up and running.

[Ltank]

Re: Phillips 42pfl7432 no backlight

Good job! do you have a pic of where the Zener diode was with the old or new diode as a reference for others because you did not list the D### number so we can find it. Whats the difference between Mod 1 and Mod 2 ? The Mod papers said it did not matter if Mod 1 was done. Are both Mod 1 and 2 required to work properly?
Thanks