Sony KDL-40ex400 LCD tv no power...100% dead

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

usa 110/120v

[selldoor]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

Ok - its easier if you change it in the profile then we can see what voltage we are dealing with from the outset.
Pictures are not really clear enough for troubleshooting- On one near the connector
with multicoloured wires there are 2 torpedo like components - maybe yellow?- are they marked on the board as being fuses - did you check them. There are also a number of fusible resistors
pale fawn colour - maybe test those as well?

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

hi....all caps and fuses check ok...as i stated earlier

thanks

[budm]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

hi....all caps and fuses check ok...as i stated earlier

thanks

Do you have ESR Meter to test the cap?
Can we get better pictures, and also the pictures of the bottom side so we cab see the damaged pads?

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

yes tested caps all good esr meter used....and all flat tops

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

the damaged pad is not an issue i jumped it to next area in same trace

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

ill try to post better pics later....

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

but please can u answer this question

applied 3.3v to pwr on pin

did not pwr on power supply

what does this mean

[budm]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

So let me see if I get this correct, you do have have 3.3VDC standby voltage, then you applied force on to the POWER ON (PS_ON) pin, nothing happen? I will see if shopjimmy has good clear pictures of your power supply board so I can give you the voltage test points to test.

[budm]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

Here is the diagram for the power supply.
Check the DC voltage between Sourc and Gate of Q6201 to see what you have when 3.3V is applied to POWER ON pin.

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

correct......and when i do this i get no voltages at 12v or 24v pins

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

thanks i will do later dobt have board here.....ill let u know

[budm]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

we need to find out if that MOSFET Q6201 does get the Voltage to turn it on or that voltage got routed to ground by the temperature sensing circuit.

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

i dobt see a Q6201

[budm]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

It is on the bottom side of the board.
http://www.shopjimmy.com/media/catal...1-bottom_1.jpg

http://www.shopjimmy.com/media/catal...2-11-top_1.jpg

Q6201, 202, 203 are sitting next to each other.

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

ok i see it.....dang hard to see.....not sure what legs are what though....d s g

[budm]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

Looking at it with two legs pointing down and the center leg on the top: the left leg is Gate, the top/middle leg is Drain, the right leg is Source.
Example:
http://www.datasheetdir.com/ZXMN2B14...hannel-MOSFETs

Do not let the probes slip!

[Agent24]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

Look up the part number and find datasheet, that will tell you the pinout

Whoops, Budm already did.

[shelby5041]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

ok i get 2.1v

s-g on Q6201

[budm]

Re: Sony KDL-40ex400 LCD tv no power...100% dead

OK, then check Source and Drain next.