Sony KDL-32L504 No Power ....Dead

[tom66]

Re: Sony KDL-32L504 No Power ....Dead

1 ohm is far too small -- I said 10 ohm 1W would work, or 10 ohm 5W.

1 ohm draws 3.3A for a standby line that is far too much.

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

ok, i guess i will need to get a different resistor. hope i did not damage anything else.

i re-read your post .......sorry i did not read it correctly the first time. you did say to use the 10ohm 1Watt resistor ......my bad........

i will try again tomorrow.

do you think i damaged anything?

[tom66]

Re: Sony KDL-32L504 No Power ....Dead

Unlikely to be any damage... PSU will have just shut down.

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

ok......this time i used a 10-Ohm 1Watt resistor.

I did the same thing as before. Connected one resistor lead to the STBY node and the other lead of the resistor to the chassis ground..........

I plugged the power into the tv and measured the DC voltage at the STBY node.

I measured 3.3V........it was constant and did not fluctuate........

So what does this mean? Does this mean the power supply board is ok?

[tom66]

Re: Sony KDL-32L504 No Power ....Dead

It would seem to indicate the main board has a short somewhere.
This trick could be useful:
https://www.youtube.com/watch?v=XhqwC3BFBug

[selldoor]

Re: Sony KDL-32L504 No Power ....Dead

Perhaps post good clear straight on pictures of the main board front and back (do not rotate it keep the top at the top - perhaps we can spot something.

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

i will post pics once i get home from work tonight. thanks again.

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

I am enclosing pics of the front and back of the logic/video board

any additional ideas on how to find this short would be appreciated.

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

see enclosed pic.

Device1 and Device2 are N-channel enhancement mode devices

Link to datasheet is here

http://www.anpec.com.tw/searchProduc...&keyword=2513n

When i measure device 2 from Source to Drain ......using ohms measurement i get a reading of ~ 18Kilo-ohms. When i make the same measurement on device 1 i get a reading of ~ 4.5Meg-ohm.

is this a sign of anything?

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

ok...i found that i think that 18k measurement is valid.

See enclosed pic.....i have tried to show that there is an 18k resistor ......one lead of resistor goes to source node and one lead goes to drain node thus the reason for me measureing 18K across source to drain......

any other ideas on how to find the problem? or should i just tell neighbor cant fix it.

[tom66]

Re: Sony KDL-32L504 No Power ....Dead

That is a DC-DC converter -- what does the output measure? If the output is shorted, the power supply might see a short too.

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

i can make a measurment......just not sure where to measure and when. Recall that the voltage goes away quickly when ever i connect this cable to the main/logic board.

where would i measure to verify operation?

[tom66]

Re: Sony KDL-32L504 No Power ....Dead

Sorry I can't see the full number -- there's a brown-ish cap with "C...72". This should be the output. Sorry I didn't mention this at first -- was in a rush.

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

i am enclosing a pic with an arrow ....the arrow is pointing to what i believe is the cap you're referring to..........is this the cap you want me to measure....is there a particular side of the cap i should measure on?

[tom66]

Re: Sony KDL-32L504 No Power ....Dead

Yes -- all you need to do is measure across it on 20 VDC range.

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

ok....sorry not replying sooner than today but i have been sick with the flu........knocked me on my butt. Almost better now. Anway, i made the measurement but i already knew the outcome.......

the voltage measured across that cap was about 0.4V. Which is no surprise really .......right...............because there is a short some where which causes the TV to essentially turn off......

anyway, if no new good ideas on how to fix......i think i am done with this.

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

i guess no new ideas?

[Welchs101]

Re: Sony KDL-32L504 No Power ....Dead

I wanted to thank those that helped me try and figure out the problem with this monitor. I love tinkering and trying to get things that are broken ....fixed.

Thanks again. Love this forum.

[stanm]

Re: Sony KDL-32L504 No Power ....Dead

I have the same TV with the same problem, only I don't hear a click when I turn the TV on. I did a couple of measurements and got 3 volts going to the controller board but that is all I have done so far. what did you actually find out the problem was? I am going to trouble shoot the Power Board doing what you did and hope to find something.

[dpiroli3]

Re: Sony KDL-32L504 No Power ....Dead

ive worked on one of these b4, it was the ir board pulling down the standby 3.3v. unplug the ir board and try to turn it on again.