Rca led50b45rq

[budm]

Re: Rca led50b45rq

OK.. I think I've finally got what you're looking for. Between PIN 12 (yes, the one we've referred to the entire time) and that point you marked (which i believe is C5 capacitor on the other side), i got 1.4-13 on the 200 scale. ALSO, this time between the out going side of resistor 000 and PIN 12, i got 5.7-195 on the 200 scale.

It should be steady and < 1 Ohm between the two points.

[x_orange90_x]

Re: Rca led50b45rq

�� it fluctuated within the range given. it would rise then drop down to around 1.4 and then back up. this was with the lowest setting on my Meter.

[budm]

Re: Rca led50b45rq

It should read about the same as when you touch your meter probes together. It sounds like you have bad connection. It is just simple connection from point A to point B

[x_orange90_x]

Re: Rca led50b45rq

It should read about the same as when you touch your meter probes together. It sounds like you have bad connection. It is just simple connection from point A to point B

when i touch the probes together i get 1.4 just like the lowest reading i got checking those points.

[budm]

Re: Rca led50b45rq

How about the readings on all other pins of that IC against the test point where the black probe is? Any of them showing steady 1.4 Ohms?
Something is not making logical sense right now.

[x_orange90_x]

Re: Rca led50b45rq

All of the other pins showed a solid 1 to the left (out of range).
Edit - i just checked again. Now I'm getting a steady 1.2 from the test point to pin 12, and a steady 1.3 from resistor 000 to pin 12. I was using the red probe with a safety pin attached for more precision, but apparently that was causing a discrepancy.

[budm]

Re: Rca led50b45rq

All of the other pins showed a solid 1 to the left (out of range).
Edit - i just checked again. Now I'm getting a steady 1.2 from the test point to pin 12, and a steady 1.3 from resistor 000 to pin 12. I was using the red probe with a safety pin attached for more precision, but apparently that was causing a discrepancy.

So you have 12V at the 000 Ohm resistor which is connected to pin 12 of the IC but pin 12 is showing only 0.28V, so what do you think? May be you were not getting good probe contact to pin 12 when you were testing the Voltage?

[x_orange90_x]

Re: Rca led50b45rq

So you have 12V at the 000 Ohm resistor which is connected to pin 12 of the IC but pin 12 is showing only 0.28V, so what do you think? May be you were not getting good probe contact to pin 12 when you were testing the Voltage?

I had thought the same thing this morning. I don't remember if i had been using the safety pin when i checked all of those voltages, but i suppose i can try again without it in case. It sounds to me like you're saying there HAS to be more voltage there than i reported previously, based on the resistance. The datasheet says that the VCC should be operating around 17v.

If i do in fact have the correct voltage there when i check again, what direction would that lead us in?

Btw, would you like me to check ALL of the pins voltages again, or just pin 12?

[budm]

Re: Rca led50b45rq

At this point recheck the VCC again with good probes to see what you have. I need to look at the spec sheet of the IC to see what is the startup Voltage is, LOW shutdown Voltage, High shutdown, etc.

[x_orange90_x]

Re: Rca led50b45rq

Just finished checking PIN 12 voltage again. With the set in Standby i got around .5v, with it switched on the highest reading i got was 1.01v with a steady decline. However, i unplugged the LEDs and switched it ON again and got 12.95v steady. With the LEDs plugged in, the voltage drop started to occur after the screen flashed and went black.

I have attached the Datasheet for the L6599AD IC for you.

[budm]

Re: Rca led50b45rq

Just finished checking PIN 12 voltage again. With the set in Standby i got around .5v, with it switched on the highest reading i got was 1.01v with a steady decline. However, i unplugged the LEDs and switched it ON again and got 12.95v steady. With the LEDs plugged in, the voltage drop started to occur after the screen flashed and went black.

I have attached the Datasheet for the L6599AD IC for you.

That is NOT PFC IC, that is the SMPS IC for the main power supply. https://www.badcaps.net/forum/attach...3&d=1489774812
The PFC IC is the one on the top right, it is 8-pin SMD IC.
It seems like that SMPS IC is trying to run but since you do not have the PFC Boosted Voltage from the PFCC section so it goes into shutdown.

[x_orange90_x]

Re: Rca led50b45rq

I'm a little bit confused now. What do i need to do?

[budm]

Re: Rca led50b45rq

Need to get the P/N of that PFC Controller IC to find out if it is getting the VCC to run when PS-ON is present.

[x_orange90_x]

Re: Rca led50b45rq

Here is the P/N for that IC:

4863-2
H1335

[vinceroger69]

Re: Rca led50b45rq

this should be the data sheet maybe measure pin 8 vcc pin and see what voltage you get
https://cdn.badcaps-static.com/pdfs/...7e28445b8e.pdf

[x_orange90_x]

Re: Rca led50b45rq

this should be the data sheet maybe measure pin 8 vcc pin and see what voltage you get
https://cdn.badcaps-static.com/pdfs/...7e28445b8e.pdf

To EC1-, correct?

[vinceroger69]

Re: Rca led50b45rq

yes just be carefull your probes dont slip etc as dont want too cause more dameage whilst your testing the ic you might as well take all the pin readings in one go.

[x_orange90_x]

Re: Rca led50b45rq

Here are the results:

OFF Standby

(1) VSENSE - 1.07v
(2) VAOUT - 0.04v
(3) MULTIN - 1.63v
(4) ISENSE - 0v
(5) DETIN - 0v
(6) GND - 0v
(7) GTDRV - 0.01v
(8) VCC - 0.04v

ON

(1) VSENSE - 1.07v
(2) VAOUT - 0.05v
(3) MULTIN - 1.63v
(4) ISENSE - 0v
(5) DETIN - 0v
(6) GND - 0v
(7) GTDRV - 0.03v
(8) VCC - 13.9v drops to 0v

ON - LEDs Unplugged

(1) VSENSE - 2.52v
(2) VAOUT - 2.62v buzzing sound
(3) MULTIN - 1.29v
(4) ISENSE - 0.01v
(5) DETIN - 2.03v
(6) GND - 0v
(7) GTDRV - 2.94v
(8) VCC - 13.99v drops to 0v

[budm]

Re: Rca led50b45rq

Can you verify that PS-ON Voltage did not drop out when the VCC drops down to 0?
You are getting the same VCC Voltage drops out on the SMPS IC too, same power supply is used to supply the VCC to both ICs which is generated by the AUX winding of the standby power supply transformer that I drew up the diagram in the picture for you to trace out the Voltages.

[x_orange90_x]

Re: Rca led50b45rq

PS-ON remains a constant 3.54v regardless of the VCC drop out. Also, with the LEDs unplugged, PS-ON is a constant 4.89v.