Sony KDL-65W850A Dead

[kevinm34232]

Re: Sony KDL-65W850A Dead

The 1110021 is the regulator (SN1110021PWP). Measure the dc voltages on the pins.

I thought we were talking about this regulator..?? Not the connector.


I did not use a resistor. I want to make sure the backlights come on to confirm the main board. Should I just be able to jump the PS-ON and BL_ON? Use a resistor for the BL_ON only?

[dick_barton]

Re: Sony KDL-65W850A Dead

A resistor is used to protect the power supply from being accidentally short circuited to what you are connecting to especially if there was a fault. That would explain why you said it was pulling the 3.3V down to 0V.
You should use a resistor between STB3.3V to Power_ON and then another resistor between Backlight_ON and either STB3.3V or REG12V. Use 1K resistors.

[kevinm34232]

Re: Sony KDL-65W850A Dead

How do I know if BL_ON should be 3.3 or 12V?

[dick_barton]

Re: Sony KDL-65W850A Dead

I don't know not having any information on the set but give it a quick try using the 1K resistor from Reg12V to Backlight_On since you already said that connecting to the STB3.3V did not work.

Edit
I should also add with the main board disconnected.

[kevinm34232]

Re: Sony KDL-65W850A Dead

No it's not working with 12V either.

[dick_barton]

Re: Sony KDL-65W850A Dead

What are the voltages on the BL_ON pin and BL_ERR pins before and when you apply 12V.

[kevinm34232]

Re: Sony KDL-65W850A Dead

Could it be a backlight issue and power board causing the main board not to turn on the PS because of an error, or do you think the main is bad? I haven't worked on many Sonys, but I remember a couple and it wasn't easy to diagnose backlight issues. The SM is pretty much useless..

[dick_barton]

Re: Sony KDL-65W850A Dead

That's what we are trying to establish with the test so as to rule in or out the main board.
Whats the model number of the power supply APS-xxx?

[kevinm34232]

Re: Sony KDL-65W850A Dead

APS-352 and APS-356 is second PS. I don't have a 1k resistor, but I do have a bench 5a 30V power supply I can use. BTW the second PS board, AC is connected from one to the other, but I only 1 have 1VAC at the 2nd bridge rectifier, not sure if it is supposed to kick on with a relay somehow..

[kevinm34232]

Re: Sony KDL-65W850A Dead

Little update.. When jumping PS_ON with the main board disco'd, I get 6.1V for BL_ERR, and 0.2V for LD_ERR off the top connectors that connect the 2 power boards, but not the connector going to the main board.

[dick_barton]

Re: Sony KDL-65W850A Dead

Little update.. When jumping PS_ON with the main board disco'd, I get 6.1V for BL_ERR, and 0.2V for LD_ERR off the top connectors that connect the 2 power boards, but not the connector going to the main board.

So you have BL_ERR = 6.1V when you have:-
PS_ON jumpered to STB3.3V and BL_ON jumpered to 12V.
Is the BL_ERR = 0V prior to applying the 12V. If so it looks like you have a backlight problem.

[kevinm34232]

Re: Sony KDL-65W850A Dead

No the BL_ERR = 6.1V when just PS_ON is jumpered, I haven't tried jumping BL_ON at the same time.. That should be done as if the signal was coming from the main board correct?

[dick_barton]

Re: Sony KDL-65W850A Dead

You jumper them both at the same time with the main board disconnected and then measure BL_ERR if the backlights fail to come on.

[kevinm34232]

Re: Sony KDL-65W850A Dead

OK I applied 3.3V to PS_ON, and 12V to BL_ON.

BL_ON drops to 6.1V, and BL_ERR is also at 6.1V.

[dick_barton]

Re: Sony KDL-65W850A Dead

I must admit I don't know what else to do at this time not having any schematic to check through.
It does look as though you have a backlight error but I would wait and see what others make of the results.

[kevinm34232]

Re: Sony KDL-65W850A Dead

OK thanks.

On Sony, are we sure if BL_ERR is usually high or low when there's a problem?

[dick_barton]

Re: Sony KDL-65W850A Dead

I'm not familiar with the set so I don't know.

What voltage do you have across the capacitors marked on the two 160V 220uF (hard to read) close to the leds when you attempt to switch out of standby with everything connected? It may only be a brief pulse. I'm thinking that you have a led fault.

[budm]

Re: Sony KDL-65W850A Dead

All board connected. What DCV do you have at the AC-OFF DET pin? <1V = bad, >3V or so = good.

[dick_barton]

Re: Sony KDL-65W850A Dead

but I only 1 have 1VAC at the 2nd bridge rectifier, not sure if it is supposed to kick on with a relay somehow..

Which (and where) second bridge rectifier. I only have the pictures you provided as a guide.

[dick_barton]

Re: Sony KDL-65W850A Dead

Hi Budm
Here are some measurements given earlier.

3.3V at AC_Off-Det, and 0v at PS-ON. I jumped PS-ON from the 3.3STBY, and then the REG+12V comes up. I still can't figure out where the test points are for DC/DC converter on the main board, but all the fuses are good and have either 12v or 5v.