Sony kdl52s5100. No picture no sound

[audiofreak19]

So I just picked this tv up and I plug it in and only one relay clicks when you press the power button. The guy said two used to click. So I check the power on the power board and the backlight and I think it was the inverter one or something like that were reading less then a volt meaning something is not sending enough power to turn the inverter on. Or the two inverters that are on the tv are bad. I don't really know where to start looking next. I visually checked out the main board and it looked ok. I checked all the fuses. And I checked all caps on the tv. What should be my next step.

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

Also I already checked the fuse on the t con board. And it read fine. I'm thinking either the backlight inverters are bad or the main board. Cause where I measured the back light power on the power board. The harness was going to the main board. And read like .384v dc.

[budm]

Re: Sony kdl52s5100. No picture no sound

Down load these two service manuals, I am downloading it right also.
http://elektrotanya.com/?q=showresul...oria=&kat2=all

Do you see any LED error codes?

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

I tried downloading the service manual and capped out on my daily limit. But no led error codes which leads me more towards the main board.

[tom66]

Re: Sony kdl52s5100. No picture no sound

Got 5V standby from power board? It's steady?

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

I actually have 3.3v standby. And 3.3v on the pwr on after I turn it on.

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

And it is steady at 3.3v

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

All the other pins read what's marked on the board.

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

If it's not getting the correct standby voltage. That would lead to somethig messed up on the power board right? Also I have no problem turning the tv on and off with the power button.

[budm]

Re: Sony kdl52s5100. No picture no sound

Service manual. I am surprised that there is no error codes at all.

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

That's the wrong service manual. The model is kdl52s5100. And yea the green light lights up no problem and stas solid. Only thing I could think of is main board cause in the trouble shoot error codes it doesn't have one for a main board issue.

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

So I got on another computer and looked at the service manual and it shows the standby voltage is supposed to b 3.3v

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

What does ac off det mean.

[budm]

Re: Sony kdl52s5100. No picture no sound

Oops!, I upload the wrong one (was working on w5100).

[Jonesy123]

Re: Sony kdl52s5100. No picture no sound

I have a kdl52s4100 been playing around with it for a while now, everything I've read and tested says its a bad main logic board, apparently for mine there is a repair service but I'm too cheap. Ill figure it out one day.

[budm]

Re: Sony kdl52s5100. No picture no sound

That circuit detect if the input AC is too low or not, at normal that AC OFF DET pin will be high, if it is low, the backlights circuit will not allow to turn on.

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

I wanna say if I remembered correctly when I metered it the ac det didn't read anything even while the tv was on.

[budm]

Re: Sony kdl52s5100. No picture no sound

If you look at the SCH, the incoming AC is rectified by D6502 the b+ out will bias on MOSFET Q6501, which will ground out the bias for MOSFETQ6502 so the LED inside the opto PH6501 will be off, so the photo-transistor inside the opto will also be off so the Collector voltage of the opto PH6501 will be high.
So check the voltage of that circuit, make sure to use the correct ground point (the negative leg of the main filter) for the primary side of the circuit.

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

10-4. I will try it in the morning once I get off work.

[audiofreak19]

Re: Sony kdl52s5100. No picture no sound

So the ac det is reading the same voltage as the stand by voltage of 3.39v. And the back light is reading .389v