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L04.1U.AA Dead    
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pensacol



Joined: 02 Jul 2009
Posts: 30

PostPosted: Thu Jul 02, 2009 8:56 pm    Post subject: L04.1U.AA Dead Reply with quote

My 32" philips went through a power surge last week. Now here I am trying to repair it.

Replaced bad IC7531 (Drain shorted to ground),
replaced fusible resistor 3532, 3513, and 3514,
replaced dead 7512 mosfet.

Manual says IC7531 charges capacitor c2532 and starts to switch at 9.5 volts. Voltage won't go above 4.89vdc at c2532, so the IC won't start to switch.

I have 168vdc on pin 14. I can't for the life of me figure out why I can't get the required 9.5v to start the IC. Can somebody help me please! I miss my tv.
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JTS1957



Joined: 21 Jan 2009
Posts: 2395
Location: Far, Far Away

PostPosted: Fri Jul 03, 2009 1:45 am    Post subject: Reply with quote

Found:

loc# part#
7511 935272043118
7512 932216716687
7531 935273952112

Also:

Replacing 7531, 3532, and 6533 & 6536 fixed it (IC, resistor, and diodes).
pensacol



Joined: 02 Jul 2009
Posts: 30

PostPosted: Fri Jul 03, 2009 8:43 pm    Post subject: Reply with quote

Thanks for the help. Found bad 6533 and 6536 and replaced, but no change. Still have 4.98vdc. Any more suggestions. My head is starting to hurt looking at these schematics trying to find a diode that could drain the voltage somewhere. Now I remember why I don't fix tv's anymore!
pensacol



Joined: 02 Jul 2009
Posts: 30

PostPosted: Fri Jul 03, 2009 10:16 pm    Post subject: Reply with quote

Ok I changed IC7511 also, and now the set will turn on, but I get no picture or sound and the led blinks 5 times and then 1 long blink. I checked the manual for the LED blinking codes and if I'm reading it right it says error 5 is +5v protection. Where would I begin to look for that.
pensacol



Joined: 02 Jul 2009
Posts: 30

PostPosted: Fri Jul 03, 2009 10:41 pm    Post subject: Reply with quote

Update: I left the set turned on to and the power light started blinking irradicly and then blew the main fuse. Now the set will blow the main 4 amp fuse as soon as it is plugged in. I have tried unplugging the degaussing coil, but it still blows instantly.
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JTS1957



Joined: 21 Jan 2009
Posts: 2395
Location: Far, Far Away

PostPosted: Sat Jul 04, 2009 12:03 am    Post subject: Reply with quote

That's the problem with surges, may be one or two parts, or a whole freight train (of indeterminate length). Laughing
pensacol



Joined: 02 Jul 2009
Posts: 30

PostPosted: Sat Jul 04, 2009 7:58 am    Post subject: Reply with quote

Yeah tell me about it. I must have replaced a total of about 13 parts so far. And it still doesn't work. Just my luck it took the hercules chip out. Do you know of anywhere that you can buy new or used mainboards?
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