How I repaired a Toshiba 32" LCD

[Dumah Brazorf]

Hi,
I successfully repaired a 32AV734G1 by Toshiba striked by a lightning.
Sorry i forgot to take photos...
I found signs of an electric arc on the chassis under the main line connector of the power board so I focused on that board initially. It's a 715g3714-p01-h20 (vestel crap?) Found the schematic here.




Main fuse F901 blown, inrush thermistor limiter NR901 destroyed, main bridge rectifier BD901 shorted ac to negative, R955 bad. Also changed Q970 and Q971 for good. Checked all the diodes and all caps and the cold side of the board for shorts. All green.
Fired it up... quite literally. R958 and IC950 smoked out. IC950 is a A6069H PWM controller with integrated mosfet. The mosfet was shorted out, probably I didn't figured out in precedence, and killed the resistor. Found one of the zener diode ZD951 around IC950 not reading good.
Now the power supply didn't power up, 5V not present. 5V is produced by the transformer driven by IC950. All diodes, resistors and caps around IC950 measured good so I finally changed all zener left on the hot side of the power board. That worked.
Checked the main tv board and the inverter board of the tv. No signs of whatsoever, no shorts.
Reassembled and tested for some hours. So good so far.

So, the lesson of today is: never trust a glass zener!

[dskall]

Re: How I repaired a Toshiba 32" LCD

Thanks for sharing repair

[koka0011]

Re: How I repaired a Toshiba 32" LCD

thanks for the information