Sony KDL-32EX340 not powering on

[OldMan]

I recently received an entire house full of electronics from a friend who had lightning strike and destroy the majority of his electronics. I've already fixed a handful of items but this TV is giving me a little trouble.

Issue when I received it was TV will not power on using keypad or remote.
I measured voltages on PSB and did not get 5V STB at the pin to mainboard but did have 120V going into the PSB. I first tried to replace this board, but still no voltage going to mainboard even in standby.

My first instinct tells me even the new PSB is bad, but maybe not. Is it possible lightning strike has fried the IR control board and my attempts to power on are not working because this is the culprit? Any other guesses as to what might be the issue here? Any and all feedback much appreciated!

[selldoor]

Re: Sony KDL-32EX340 not powering on

Please can you update your profile with country and mains voltage.
Decide which board you want to trouble shoot and post a good clear picture front and back. You of course can duplicate the tests on the other board but to work on two boards is just too confusing (its difficult enough with one)
I wouldnt have thought the IR board would be fried but lightning strikes are hard to guess.
You can test (to some extent) the remote control by viewing the led through a digital camera when pressing a button.

[OldMan]

Re: Sony KDL-32EX340 not powering on

Info has been updated, I'm in USA with 120V.

I have included here both boards for sake of being complete. I would like to only troubleshoot the old board because both new and old are giving me same bogus readings at the pins going to main board. No pin reads over 350mV on either board. I will be returning the junk new one.

Old board:

[OldMan]

Re: Sony KDL-32EX340 not powering on

New board:

[budm]

Re: Sony KDL-32EX340 not powering on

Please also post the pictures of the whole back side of the TV so we can see how all the boards are connected together.

[ivoh]

Re: Sony KDL-32EX340 not powering on

check the 5vsb with all other boards unplugged from the psu

[OldMan]

Re: Sony KDL-32EX340 not powering on

check the 5vsb with all other boards unplugged from the psu

Both new and old boards show anywhere from 50-100mV on the standby pin when all cables except AC in are unplugged.

Attached is a photo with all boards and their connections.

[selldoor]

Re: Sony KDL-32EX340 not powering on

Bit of a shame but the Picture of the old board needs to be a bit clearer - I can see much more detail on the new one, but we need to see the old one clearly.
There is a small transformer between the BIG 400v cap and the edge of the board
can you check the soldering on it - looks a bit odd in the picture.

Are you confident to test high voltages? 300-400 volts say?
If so can you connect the power supply to the mains, set your meter on 600vdc and
very very carefully put a probe onto each leg of that BIG capacitor.
If the board is off the set make sure you are working on a non conductive surface and dont touch any part of the board other then the capacitor with the probes.

[OldMan]

Re: Sony KDL-32EX340 not powering on

Hopefully you will find these new pictures of the old board a bit more helpful.
Two lighting conditions just to be sure.

Both new and old boards read 164.7V on the biggest cap (a 450V).

Edit: When connected to main, the old board starts around 300V and slowly drops in voltage as I measure, the one one holds steady at 164.7

[budm]

Re: Sony KDL-32EX340 not powering on

Check the fusible resistor R6301 to see if it has open circuit, it is for feeding the B+to the STBY SMPS IC 6301 (MIP2H2).
Also take the resistance reading between pin 7 (8 is tied to 7) and the other pins, then report the reading.

http://www.shopjimmy.com/media/catal...254-11-top.jpg
http://www.shopjimmy.com/media/catal...-11-bottom.jpg

[bammbammfran]

Re: Sony KDL-32EX340 not powering on

I would first check for 12v at the low side in case you did not get the right ground at the connector.

Set the power supply alone on a non-conductive surface. plug power into the board, THEN into the wall

Check voltage at the capacitor at the red and black circle
If no dc
then back to the high power side
and check for near 160+ between the yellow and red + next to it (this is the main cap again)
then leaving the neg test probe in place on yellow check the smaller red circle
at the same time you can check the resistor that bud m mentioned by using again the yellow as ground and red at the other side of the board at the group of 4 pins in the red circle.
if 160+ at all points
Unplug power, let sit 10 minutes
then check resistances
blue to red green to red and blue to green
and on the ones Budm asked for on the 7 pin IC

[OldMan]

Re: Sony KDL-32EX340 not powering on

R6301 is approx. 4 MOhm on both boards and no open circuit.

Pin resistance as 7 to x, all registered in MOhm levels. Very similar numbers for both boards.

1 6.6 M
2 6.9 M
3 6.9 M
4 7.19 M
5 7.3 M
6 7.1 M
8 5.1 M
9 5.5 M
10 5.6 M
11 5.7 M
12 28.4 M
13 6.3 M
14 6.4 M
15 6.6 M
16 6.6 M

[budm]

Re: Sony KDL-32EX340 not powering on

That resistor is bad, it should be around 10 Ohms, it will go open circuit if the IC is shorted out. Take the resistor out and test again.
Are you testing the correct IC? The one to test only has 7 pins., IC6301.

[OldMan]

Re: Sony KDL-32EX340 not powering on

I would first check for 12v at the low side in case you did not get the right ground at the connector.

Set the power supply alone on a non-conductive surface. plug power into the board, THEN into the wall

Check voltage at the capacitor at the red and black circle
If no dc
then back to the high power side
and check for near 160+ between the yellow and red + next to it (this is the main cap again)
then leaving the neg test probe in place on yellow check the smaller red circle
at the same time you can check the resistor that bud m mentioned by using again the yellow as ground and red at the other side of the board at the group of 4 pins in the red circle.
if 160+ at all points
Unplug power, let sit 10 minutes
then check resistances
blue to red green to red and blue to green
and on the ones Budm asked for on the 7 pin IC

Using my newly purchased board

First black and red = no voltage
Big capacitor = 164V still
Negative big cap to small red circle shows variance from 380v down to open loop and this keep cycling as long as probes connected.
162V from yellow to red across board

Resistances
Blue to red = open
Green to red = 10 mega
Blue to green = 4 mega

The real 7 pin IC
1/8 17mega
2/8 11.5mega
3/8 6.8 mega
4/8 7 mega
5/8 open on the new, 8 mega on old
6/8 7.5mega

[OldMan]

Re: Sony KDL-32EX340 not powering on

That resistor is bad, it should be around 10 Ohms, it will go open circuit if the IC is shorted out. Take the resistor out and test again.
Are you testing the correct IC? The one to test only has 7 pins., IC6301.

Resistor now testing 8.6

In my last post I put correct IC measurements

[budm]

Re: Sony KDL-32EX340 not powering on

Those reading on the IC should not all be in the MegaOhms range. I would say you have bad IC and a blown fusible resistor, the resistor will not up unless the IC had failed. So the newly purchase board the R6301 is OK? You are checking the resistance with power not applied to the board, right? The reading of 380VDC on the main cap means that the PFC Voltage booster did kick on since the VCC to run the PFC IC is generated by the same transformer of the STBY POWER SUPPLY.

[budm]

Re: Sony KDL-32EX340 not powering on

OK, now I am confused, the resistor of which board are you testing, the new one or the old one? Testing with power applied?

[OldMan]

Re: Sony KDL-32EX340 not powering on

Those reading on the IC should not all be in the MegaOhms range. I would say you have bad IC and a blown fusible resistor, the resistor will not up unless the IC had failed. So the newly purchase board the R6301 is OK? You are checking the resistance with power not applied to the board, right? The reading of 380VDC on the main cap means that the PFC Voltage booster did kick on since the VCC to run the PFC IC is generated by the same transformer of the STBY POWER SUPPLY.

All resistance readings done without power applied to the board.

Where did you get 380VDC from? I measured 164VDC on the main cap.

Both old and new have the same R6301 measurements which are apparently not consistent.

[budm]

Re: Sony KDL-32EX340 not powering on

"Negative big cap to small red circle shows variance from 380v down to open loop and this keep cycling as long as probes connected" Unless I am reading your post wrong. Also reading in MOhms in circuit of the fusible resistor does not make sense either.
The big red circle with + and the Yellow circle - are the two legs of the main filter cap. There is no other circuit in the primary side that will generate the 380V except the PFC Voltage booster circuit.

[bammbammfran]

Re: Sony KDL-32EX340 not powering on

looks like he is getting the 380 between neg of main cap pin (yellow) and the small red circle w/ + next to it on the main power mosfet