Sony KDL-40S2000 Chassis 40WAX2

[kevinm34232]

TV comes on for a few seconds with backlight, then clicks off, red LED flashes 4x, indicating backlight failure. I unplugged inverter board and still does the same thing. How can I start to troubleshoot this?

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

Can we see the pictures of the board? I believe in SONY TV, if you disconnected the power to the Inverter board then the main board will not see the feedback signal from the main board so it thinks it has problem with the inverter board, I think, I did not try that on my SONY to find out for sure. Same thing for the SONY T-CON board.
If you get the LCD panel model number and look up the spec, it will tell you which pin on the inverter board is for the error signal.

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Panel is LTY400WS-L02 can you guide me into what I'm looking for?

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

I am looking up 'LTY400WS-L02"
Updated: no luck finding the specification sheets yet.

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

S-lcd?

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

Example of CHI MEI screen spec sheet.
As you can see, pin11 of the inverter board for this CHI MEI panel is an ERROR output pin, 3.3V = OK, 0V = abnormal.
Most company does not use that pin (no error detector circuits in the main board)

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

OK so in this model you can see the 8 thicker wires from PS, 4 are 18v+ and and 4 are ground, the smaller 3 black wires go to the main board. Pin 12 has 3.2v on it when powered on until clicks off.

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

Can we see the pictures of all the boards so we see how they are connected together? I can see at least 3 fuses on that picture, F001, 002, 003, are they OK?

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Haven't had a chance to work with TV but found this..

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

So it does use the Inverter failed detection.

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Where can I chk voltages, is it looking for a 3.3 and 5v? Can I unplug the inverter board then try to bypass the detection to see if TV stays on?

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

Well, did you check the fuses as I suggested? We still need pictures so we can where else to look on the inverter board.

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Here are voltage readings at CN7009

Off On
Pin 1 - 0 - 1.6v
Pin 2 - 0 - 3.2v (when backlight breifly comes on)
Pin 3 - 0 - 1.7v
Pin 4 - 0 - 3.3v
Pin 5 - 2.3v - 0
Pin 6 - 0 - 3.3v
Pin 7 - GRD

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Fuses are good, here are some pics, sorry for the quality I only have my phone to take pics, let me know if you want some close ups of certain areas.

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

It looks like you have two inverter boards linking together, I do not see CN7009 in you pictures, what are the connectors with Red/black wires and another connector with white/gray wires?
That is a reason why we ask to show the whole set up so we can see how many boards it has and how they are link together.
Please remeber one thing, since we do not have the TV or the boards in front of us to take good details inspection, good pictures are very important when trying to troubleshoot complicated electonics equipment from afar.

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Really trying Bud, appreciate your patience.

CN7009 is on the main board, and the connector referenced in the inverter power failure circuit posted earlier. There are 7 wires, 4 go to PS board (Gnd, Power_On, Ac_Off_Det, Power5) as shown in the last pic, and 3 go to inverter board (Dimmer, Backlight, Panel_Det)

Do you know based on the schematic what Panel_Det should be?

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

OK, to fool the main board to make it thinks the inverter is OK, we need to find out the DC voltage at the Collector of Q7008 and the chassis, it should be close to 0V right now if the inverter circuit is bad, please verify that then I can tell you what to do next.
Did you download the training and service manuals?
http://elektrotanya.com/?q=showresul...oria=&kat2=all

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Yes I did that's where I got the power failure info. Let me try to find Q7008 now not much labeled on the board

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

Or R7066? which is in parallel with Q7008 E-C

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

OMG Those components are on the bottom of the board I was trying to get to bottom of board w/o removing all the connectors and wound up breaking one off the board. Oh well. Tomorrow Im picking up the same model from someone with a broken screen so it's not a total loss maybe that connector can be fixed.