led46c45rq no backlight

[budm]

Re: led46c45rq no backlight

The PFC Voltage booster is not working, it should be >360VDC on that main filter cap when ON/OFF pin is forced on by the resistor.
So more in depth troubleshooting will be required in the PFC circuit.
We will need good clear straight shot pictures of the bottom side of the board to locate the PFC Controller IC, and then get the spec. sheet to get the pin out for the VCC pin.

[ricosavy]

Re: led46c45rq no backlight

The on/off pin is not connected to power supply the standby is actualy jump to side where it says on/off.look at this picture

[budm]

Re: led46c45rq no backlight

"The on/off pin is not connected to power supply the standby is actualy jump to side where it says on/off.look at this picture" what?
you need One resistor between 5STBY and the ON/OFF pin and another resistor between 5VSTBY and the BL_ON pin.

[ricosavy]

Re: led46c45rq no backlight

I looked at it did not see the trace from resistor to on/off pin connector did continuity test from one side resistor to standby it there was continuity but none from other side of resistor to on/off pin

[ricosavy]

Re: led46c45rq no backlight

Here pic

[budm]

Re: led46c45rq no backlight

So you are saying that the ON/OFF pin does not have trace connected to it?
I will have to look at the board layout again then.
SJ has good pictures of your board.
http://www.shopjimmy.com/rca-re46hq1...pply-unit.htm#

[budm]

Re: led46c45rq no backlight

OK, if you look real close at the board, you can see the trace leading from the ON/OFF pin to the resistor R16.

[ricosavy]

Re: led46c45rq no backlight

I looked at did not see a trace going into the pin which i thought was strange since there is a wire in the connector for that pin

[budm]

Re: led46c45rq no backlight

The trace is under the white paint.
You can check the resistance between ON/OFF pin and the R16 as I show in the picture. It has to have connection otherwise the board won't be working.

[ricosavy]

Re: led46c45rq no backlight

Ok maybe why i missed did not under white paint

[budm]

Re: led46c45rq no backlight

so the PFC Voltage booster circuit is not working and need to find out why.

[budm]

Re: led46c45rq no backlight

BTW, SMD IC1 is the PFC Controller IC. We need P/N of that IC1.

[ricosavy]

Re: led46c45rq no backlight

It is 4863-2

[budm]

Re: led46c45rq no backlight

TDA4863:
https://cdn.badcaps-static.com/pdfs/...052481c52d.pdf
You need to check the DCV between GND and the VCC pin.
Do not let the probes slip on you and since you are working in the HOT side, do not touch anything.

[ricosavy]

Re: led46c45rq no backlight

I checked the vcc to grnd i am getting .001 to .006 varies up and down.how much voltage i am i suppose to have there

[budm]

Re: led46c45rq no backlight

I checked the vcc to grnd i am getting .001 to .006 varies up and down.how much voltage i am i suppose to have there

You have to look at the spec sheet.

[ricosavy]

Re: led46c45rq no backlight

it is 10v min to 20v max. Does that mean the chip is bad since i don't even have a 1v.

[budm]

Re: led46c45rq no backlight

Check the resistance between VCC and the GND pin.
It is either the VCC has low resistance to GND or the switched transistor, Zener diode, etc that feeds the PFC IC is/are bad.
I will have to trace the VCC trace to see where it goes to on the board.
The VCC for the PFC IC is generated by the AUX winding of the STBY transformer, the rectified Voltage is then fed into the switched transistor which is turned on when the power supply board receives the PS_ON signal from the main board.

[ricosavy]

Re: led46c45rq no backlight

I checked the resistance on vcc to ground it was pretty high from thousand but it keep moving up and down.also since resistance was not low followed the trace off to a npn mps2222a one legs was bent but since it was soldered you could not tell it was broken the leg.So transistor was probably problem why the vcc was not getting power.the only problem like you said don't let you hand slip.As was testing tf12n60 for voltage my probe sliped and grounded it out pop there went mosfet 600v 12a.Also took out my t4a 250v fuse.price parts with shipping it was around 17 to 20 dollars found a power supply for 15 and free shipping so i went ahead just ordered it.I will let you know when i get it.

[ricosavy]

Re: led46c45rq no backlight

Here the one i shorted out when my hand slipped