RCA LED52B45RQ Will not turn on

[budm]

Re: RCA LED52B45RQ Will not turn on

OK, what are the DCV rating of the caps EC7, EC201, EC202 by the LED connectors? Right now it looks like the L+ of 81VDC is too low.
Check the DCV between GND and the + LEG of EC7.
Pictures provided by shopjimmy.
RCA RE46HQ1350 Power Supply Unit.
http://www.shopjimmy.com/rca-re46hq1...pply-unit.htm#

[budm]

Re: RCA LED52B45RQ Will not turn on

Nest, please check the resistance between GND and pin 1, 2, 3 of both LED connectors.

[nstlfrk]

Re: RCA LED52B45RQ Will not turn on

OK, what are the DCV rating of the caps EC7, EC201, EC202 by the LED connectors? Right now it looks like the L+ of 81VDC is too low.
Check the DCV between GND and the + LEG of EC7.
Pictures provided by shopjimmy.
RCA RE46HQ1350 Power Supply Unit.
http://www.shopjimmy.com/rca-re46hq1...pply-unit.htm#

ec7 - 100v100uf
ec201 - 160v47uf
ec202 - 160v47uf

pins 1 2 3 measure between .39 to .41 when set on 20k

the + leg of ec7 measures at 82.4v

[budm]

Re: RCA LED52B45RQ Will not turn on

ec7 - 100v100uf
ec201 - 160v47uf
ec202 - 160v47uf

pins 1 2 3 measure between .39 to .41 when set on 20k

the + leg of ec7 measures at 82.4v

OK so the Voltage feeding the boost converter circuit is 82V and it not being boosted up to higher Voltage for the LEDs.
https://www.badcaps.net/forum/attach...7&d=1475508101
What DCV do you have on the BL-ON pin when TV is turned on? >2.5VDC?

[nstlfrk]

Re: RCA LED52B45RQ Will not turn on

OK so the Voltage feeding the boost converter circuit is 82V and it not being boosted up to higher Voltage for the LEDs.
https://www.badcaps.net/forum/attach...7&d=1475508101
What DCV do you have on the BL-ON pin when TV is turned on? >2.5VDC?

BL-ON shows 4.8VDC when on

[budm]

Re: RCA LED52B45RQ Will not turn on

OK, we need to get the P/N of SMD IC U200 in that LED booster circuit section next.
You also need to test the diode on the heatsink in the same section, I can only see partial designation number of D20, the bar code sticker is in the way on the heatsink.?

[nstlfrk]

Re: RCA LED52B45RQ Will not turn on

OK, we need to get the P/N of SMD IC U200 in that LED booster circuit section next.
You also need to test the diode on the heatsink in the same section, I can only see partial designation number of D20, the bar code sticker is in the way on the heatsink.?

The complete part number of it looks to be D200

Now You have me at a loss now. I apologize a head if time.

What is the SMD IC U200?

I also dont see a Diode on a heat sink. Do you mean next to it?

Sorry bare with me.

[budm]

Re: RCA LED52B45RQ Will not turn on

U200, d20x

[nstlfrk]

Re: RCA LED52B45RQ Will not turn on

U200, d20x

The D20 is D200 and the Diode tested good.

[budm]

Re: RCA LED52B45RQ Will not turn on

P/n of u200?

[nstlfrk]

Re: RCA LED52B45RQ Will not turn on

P/n of u200?

Just can not read it. Sorry but it is just glossy. I cant even see markings.

[nstlfrk]

Re: RCA LED52B45RQ Will not turn on

p/n of u200?

cleaned off the chip and magnified it

here is what is on it

d31168
ob3350cp

[budm]

Re: RCA LED52B45RQ Will not turn on

OB3350 LED driver.
Need to check dcv between GND pin and Vin pin, Gnd pin and Gate pin.

[nstlfrk]

Re: RCA LED52B45RQ Will not turn on

ob3350 led driver.
Need to check dcv between gnd pin and vin pin, gnd pin and gate pin.

gnd/vin - 10.80

gnd/gate - 0.00

[budm]

Re: RCA LED52B45RQ Will not turn on

gnd/vin - 10.80

gnd/gate - 0.00

Vin is within the operating Voltage range.
So it has to drive Voltage to drive the MOSFET for the boost converter circuit. So it is either bad IC or something is keeping the IC in the shutdown mode.
Need to check the DCV of PWM pin, FB pin, OVP pin with ref. to GND pin.

[nstlfrk]

Re: RCA LED52B45RQ Will not turn on

vin is within the operating voltage range.
So it has to drive voltage to drive the mosfet for the boost converter circuit. So it is either bad ic or something is keeping the ic in the shutdown mode.
Need to check the dcv of pwm pin, fb pin, ovp pin with ref. To gnd pin.

pwm - 4.67
fb - .32
ovp - .97

[budm]

Re: RCA LED52B45RQ Will not turn on

pwm - 4.67
fb - .32
ovp - .97

They look fine, the OVP trip point is 2.0V typ.
At this point I would try new IC OB3350.

[nstlfrk]

Re: RCA LED52B45RQ Will not turn on

They look fine, the OVP trip point is 2.0V typ.
At this point I would try new IC OB3350.

Not problem other then where do I find something like this?

[budm]

Re: RCA LED52B45RQ Will not turn on

Ebay?