820-3435-B NO BACKLIGHT, ic is not sending boost signal.

bruce1129

New member
820-3435-b. voltage is 8.6 on backlight line where the boost signal should be sent to.
the ic is getting voltage in, the enable signal is present, the voltage divider resistors test as normal, the voltage on the dividers is also what it should be.
the chip was burnt and there was dirt underneath, and the feedback pad was burnt. my question is, will the chip fail to send the boost signals if the feedback pad is missing, and if so, would i jump that to pin 2 of the diode (on the side where the boost signal is sent of course) in order to fix the issue?
also, on the same note, please correct me if i am wrong, but the mosfet on the same line, its function is to allow the 8.6v from ppbus_g3h to pass through or not pass through, this is correct, right?
 

Gurmon

Member
yep, pretty much. if the feedback path is missing run wire from feedback pad to pin 2 D7701.
 
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