Sony KDL-40S2000 Chassis 40WAX2

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

Ah, so close!

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

So I picked up same model with broken screen today out of curiosity, and tested voltages

Here are voltage readings at CN7009

(original tv that shuts down)

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

(New TV that does not shut down)

Off - On
Pin 1 - 0 - 2.3v
Pin 2 - 0 - 3.1v
Pin 3 - 0 - 1.6v
Pin 4 - 0 - 3.3v
Pin 5 - 2.3v - 0
Pin 6 - 0 - 3.3v
Pin 7 - GRD

So the difference I see Bud is pin 1 (DIMMER). What do you think and what can I try while I have both these sets sitting here open?

Should I switch inverter boards and see what voltages I get?

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Switched inverter boards now Im confused, Tv shut off but pin 1 voltage was now the same 2.3v. Switch back and Tv stays on. Seems inverter board is bad but I feel Im missing something.

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

The Dimming control pin i just for dimming the backlights, some set will use 0v for lowest light output, 5V will be for maximum light output, so it is variable between 0 and 5V, some other brand may have it opposite.
The input signal for controlling the inverter will usually be, BL_ON (BACKLIGHT ON, or ON), Dimming (analog dimming will use variable voltage 0~5V, or PWM dimming control, which will be fix frequency with variable pulse width), so your dimming signal is OK.
So the TV with broken screen uses the same two inverter boards setup? and you install the inverter board from the TV that we were troubleshooting into another TV and it caused the other TV to shutdown?

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Yes that's correct, I will do it again tomorrow and check all pin voltages, shouldn't there be one feedback pin that should trigger it?

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

That panel_det pin3 of CN7009 should should be high >3VDC if the inverter is OK. 0V should mean the inverter circuit is bad, that was we were going to check before the board was damaged.

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

Well swapped inverter boards a couple of times, basically it seems the inverter board is bad, the one we were working on always shuts down the TV, the new one always stays on. The voltages are all the same but drop off when TV shuts down so no indication of what's actually wrong.

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

Now we have to troubleshoot it down to component level, not sure how deep you will want get into it.
You can start by check the transformer resistance reading compared it to the working one.
The good thing is that you have good board as a reference.

[kevinm34232]

Re: Sony KDL-40S2000 Chassis 40WAX2

OK, how do I know which pins to check?

[mcrivers]

Re: Sony KDL-40S2000 Chassis 40WAX2

hello

[mcrivers]

Re: Sony KDL-40S2000 Chassis 40WAX2

same problem plz help

[mcrivers]

Re: Sony KDL-40S2000 Chassis 40WAX2

[mcrivers]

Re: Sony KDL-40S2000 Chassis 40WAX2

what pins

[mcrivers]

Re: Sony KDL-40S2000 Chassis 40WAX2

[budm]

Re: Sony KDL-40S2000 Chassis 40WAX2

Please provide good clear pictures of the bottom side of the board, the OP did not provide the pictures of the bottom side, only the top side.
Are you having the same problem and narrow it down to the inverter board?