Olevia 337-b11 no dc

[tom66]

Re: Olevia 337-b11 no dc

That doesn't make sense, why would they do that?

[freakaftr8]

Re: Olevia 337-b11 no dc

Through a series of bridges on the circuit board. I have to be overlooking something. All the output pins on the secondary side of the transformers are also shorted to ground

[budm]

Re: Olevia 337-b11 no dc

On the secondary windings, one end of each winding will be tied to cold side circuit ground, the other end of the winding will feed the Anode side of the rectifier diode, so yes, you will read very low DCR (DC resistance) of the winding.
At this point with the power supply by itself and you force on the PS_ON pin and the result is that you still do not have PFC voltage booster working, you need to find out if the PFC Controller IC is getting the voltage at its VCC pin.

[freakaftr8]

Re: Olevia 337-b11 no dc

On my pictures which one would that be. I still have 18v shorted to ground though

[freakaftr8]

Re: Olevia 337-b11 no dc

If you cannot tell I usually ace with board repairs but when it comes to power supplies for some reason if it's not the usual mosfet failure or a diode here or there I'm lost...

[budm]

Re: Olevia 337-b11 no dc

Can I see the pictures of that 18v section, both side of the board?

[budm]

Re: Olevia 337-b11 no dc

The PFC controller and SMPS circuit is the small circuit board sitting vertically with 8 pins on it, close to the bridge rectifier.

[budm]

Re: Olevia 337-b11 no dc

I look at this thread:
https://www.badcaps.net/forum/showth...Olevia+337-B11

Which I redlined the board, I do not see 18V power supply.

[freakaftr8]

Re: Olevia 337-b11 no dc

Bud you are the man. Thanks. The 18v is here.

http://1.bp.blogspot.com/-PDAkne26cG...-237-T11-2.jpg

[freakaftr8]

Re: Olevia 337-b11 no dc

All other voltages show at least 1k ohm to ground. The 18v is 1 ohm. Definitely an issue.

[budm]

Re: Olevia 337-b11 no dc

https://www.badcaps.net/forum/attach...7&d=1363927087

As you can see, you can see the connection from the center pin of the 12V rectifier that flows through those red lines, you can lift off the inductor or jumper of that path to see if the short will go away. That will be the way to isolate the short. The rectifier can also be shorted out which needs to be checked. There is also small SMD cap C39 on the 12v and Gnd.
There is no sign that some one had replaced that rectifier for 12V and put in one that does not have Isolated tab?

[freakaftr8]

Re: Olevia 337-b11 no dc

Ok that 12 rectifier is a diode. It measures shorted all across the 3 legs only on the board. I pulled it and it's not shorted. The short is on the board it seems

[budm]

Re: Olevia 337-b11 no dc

So it's still reading short with the diode removed? Then next step is to remove the jumpers, inductor in the path to the connector.

[freakaftr8]

Re: Olevia 337-b11 no dc

I just looked at a delta power supply out of a sanyo. Similar setup. I get 365 ohms to ground on 12v side. 24v high like 26kohms.

[freakaftr8]

Re: Olevia 337-b11 no dc

Ok I removed the inductor after the rectifier and no more short.
However still no success. This boards cheap enough I may just order another and pin out this board and try to find the issue between measurements between the two

[freakaftr8]

Re: Olevia 337-b11 no dc

I'm measuring -14.8vdc at the vcc pin of the pfc ic on the stand up board of course ground is measured of the ground pan of the PFC IC

[freakaftr8]

Re: Olevia 337-b11 no dc

If my bridge rectifier is bad would I still have 5V stand by?

[budm]

Re: Olevia 337-b11 no dc

The 5VSTBY is an always on power supply, meaning it is on and running the minute you plug the power cord into the AC outlet, the 12V (18V?) and 24V are switched power supply which will come on when PS_ON signal is applied to the board.

[freakaftr8]

Re: Olevia 337-b11 no dc

well I just picked up a new power supply for this TV brand new OEM sound deal on it for 20 dollars. So I do some measurements test connected together and powered on and I get the Olivia flash screen but then as soon as it goes to a darker picture the backlight start flickering like crazy. The only way to get the back lights from flickering is to have an all white screen now I know this sounds unusual but as soon as there is anything displayed besides white it gets the backlight start flickering again I checked both of us I've got no change between when its flickering in when it is flickering except for the 24 volt DC out to the inverters that starts jumping between 22 and 24 volt. Now if I disconnect a slave inverter I have a solid 24 volt but of course I do not have a picture. I was doing some studying on this particular set up and one person had the same issue and they replace the t-con board which fixed it there is a 3-pin ribbon that goes from the tcon to the master inverter. but I can remove the LVDS from tee time and I still have a flickering background. only with both inverters connected at the same time do I get the flickering

[freakaftr8]

Re: Olevia 337-b11 no dc

after much diagnosing I have a feeling that there's something wrong in the primary inverter. When powered up the Olivia flash screen which is white shows perfect no flickering but as soon as the screen gets to a darker image the backlight start to Flicker. I can connect my laptop and as soon as I open Internet Explorer the screen shows white which causes the backlights not the Flicker anymore. I've tried heating up the inverters and cooling inverters to no avail. The 24 volt output of the power supply when this is happening likes to very and I hear settle clicking sound from the primary inverter the blue light on the inverter coincidence with a ticking sound coming from the primary inverter. I don't believe it's a power supply issue if I disconnect both inverters I get a solid 24 volts. If I disconnect either inverter leaving one connected I still get a solid 24 volts but as soon as both inverters are in circuit the backlight starts to Flickr unless it's an all white screen.