Re: Circuit voltage measurement problem.

I found on another forum that graduall drop of voltage is highly likely caused by bad capacitors. So I just had a look around the diagram and its just a guess by could this 2 cpacitors be going bad and thus the whole thing is occuring? (Circled in Red). The caps look all right but that is all I can say about them.



My guess is that TV starts (well no screen no sound but still) green light on then a voltage drop started and when it gets to about 140V the system detects a fault causing it to go into protection...

Re: Circuit voltage measurement problem.



Ah ok thanks just did it, and it measures to 298 - 300V and if its 1.4 x V AC then should be 322V aprox so its 20V off is that acceptable?

What could cause the power to spike up to 380V DC operating voltage and then gradually drop to 140V over about 10 sec period?...

Re: Circuit voltage measurement problem.



Thank a lot for reply.

I measured the voltage at pin 4 which supposed to be output pin i think and pin 1 and both show 139 to 137 V variation untill TV starts the blinking light thing which I think is protection mode of some kind as relay clicks and voltage in rectifyer drops.

If input is 232 V AC and output 137 -139 V DC does it mean rectifyer is done for? Or I should look around for defective components around it?

Still curious why does AC1 reads normal 230V and the parallel...

Hi

I got an issue with power supply section of my plasma TV. When turned on it seem to get green light like its starting and after like 10 sec goes to blinking red.

I opened up the unit and started pinpointing the culprit so found when TV just switched on at point where it supposed to be 400V to LLC_SUPPLY it goes up to 380V and decreases to about 140V then a relay click and blinking light appears voltages just gradually continues to drop. I traced it to bridge rectifier and got 230V on pin 2 when tv in that 10 sec period and goes to 0 when red light starts blinking....

Re: Metalized polyester film capacitor problem

Thank for the help at explaining what that capacitor is and does. Looks like it is not the problem as I found 2 other identical capacitors on the board to be same 355nF and 364nF so my guess if they all would be faulty the TV would not even power up.

My issue is plug it in the wall stand by red light comes up, switch it on with the remote, then light goes green for about 5 sec and then constantly blinking red until I switch it off (remote doesn't respond on switch off command). The display doesn't light up and no sound....

Re: Metalized polyester film capacitor problem

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Re: Metalized polyester film capacitor problem

Thank you for reply.

I tested the capacitor in circuit first and then soldered it out to test and got the same reading of 360 nF. I allready learned a my lesson of not taking parts out to test them spend the whole day on trying to find the faulty part when it was right in front of me just needed to test it separately. So I guess its dead or on its way there.

Do all the characteristics of capacitor apply to these ones as well or there is something different about them?
Is it just the way they made?...

Hi

I am new to all this electronic repair stuff but gotten around to fixing some of lcd monitors and now decided to takle a plasma tv repair

I got around to finding that stan by voltage is at 6.5V instead of 9.5V and every time I touch the testing points with digital multi meter for less then a sec multimiter will spike to 9.4V and goes to steady 6.5V. I traced all components along the line and got around to if I am not wrong "metalized polyester film capacitor" and its saying "470n M 275V" on the top and service manual says its suppose to...