Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

[beetle1303]

Sharp TV flashing green light 2x per second at constant rate. Various reset methods do not have any effect on it. Search here and found flashing green 2x per second indicate bad power supply, which I am quite certain now.

I am seeking help with basic trouble shooting to find the short-circuit on the secondary side that I believe is the cause:

The main PD connector:
PD-1 (PNL12V) : 0.02V
PD-2 (PNL12V) : 0.02V (fluctuating)
PD-3 (SGRN) : 0V
PD-4 (SGRN) : 0V
PD-5 (UR13.2V) : 0.05V (fluctuating)
PD-6 (UR13.2V) : 0.05V (fluctuating)
PD-7 (UR13.2V) : 0.05V (fluctuating)
PD-8 (UR13.2V) : 0.05V (fluctuating)
PD-9 (SGRN) : 0V
PD-10 (SGRN) : 0V
PD-11 (SGRN) : 0V
PD-12 (SGRN) : 0V
PD-13 (AC_DET) : 2.5V (fluctuating widely)
PD-14 (PS_ON) : 2.5V (fluctuating)
PD-15 (BU5V) : 3V (fluctuating widely)
PD-16 (PNL_POW) : 0.1V
PD-17 (NC) : 0V
PD-18 (NC) : 0V
PD-19 (DIMMER) : 0V
PD-20 (NC) : 0V
PD-21 (OFL) : 0V
PD-22 (ERROR) : 0.05V (fluctuating)
PD-23 (NC) : 0V
PD-24 (SBY) : 0V

3x Opto-couplers input: 2.5V (fluctuating widely)
3x Opto-couplers output: 2.5V (fluctuating widely)

Searched here and learned that fluctuating output voltages and feedback circuitry generally means shorted components causing PWM chip to power-cycling up and down..

If this is the case - need help to find the short(s).
I have tested all the capacitors, diode and resistors around the PD connector, all seems to be normal reading on and off circuit.
What else and where else do I start?

[Diah]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

[QUOTE=beetle1303;
PD-13 (AC_DET) : 2.5V (fluctuating widely)
PD-14 (PS_ON) : 2.5V (fluctuating)
PD-15 (BU5V) : 3V (fluctuating widely)
[/QUOTE]

run the PCB as stand alone... with out any connect to it... it sound the short outside the PCB

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

run the PCB as stand alone... with out any connect to it... it sound the short outside the PCB

Originally tested with mainboard connected, LED strips not connected.

Wow @Diah!!
This is power supply stand-alone:
PD-1 (PNL12V) : 0V
PD-2 (PNL12V) : 0V
PD-3 (SGRN) : 0V
PD-4 (SGRN) : 0V
PD-5 (UR13.2V) : 0V
PD-6 (UR13.2V) : 0V
PD-7 (UR13.2V) : 0V
PD-8 (UR13.2V) : 0V
PD-9 (SGRN) : 0V
PD-10 (SGRN) : 0V
PD-11 (SGRN) : 0V
PD-12 (SGRN) : 0V
PD-13 (AC_DET) : 0V
PD-14 (PS_ON) : 0V
PD-15 (BU5V) : 4.95V
PD-16 (PNL_POW) : 0.1V
PD-17 (NC) : 0V
PD-18 (NC) : 0V
PD-19 (DIMMER) : 0V
PD-20 (NC) : 0V
PD-21 (OFL) : 0V
PD-22 (ERROR) : 0.08V
PD-23 (NC) : 0V
PD-24 (SBY) : 0V

Opto-couplers 1: input: 1.03V / output: 0.38-042V
Opto-couplers 2: input: 0V / output: 11.05V
Opto-couplers 1: input: 0V / output: 0.14V

So confirmed the short(s) in the mainboard? If so is it possible to attempt tracing it on the mainboard?

[Diah]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

Originally tested with mainboard connected, LED strips not connected.

Wow @Diah!!
This is power supply stand-alone:

you need feed the PCB PS_ON pin from the V. you have at the socket present as STB ( (BU5V) : 4.95V ) then this will be stand alone. runing the PCB with out LED BL and MB

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

you need feed the PCB PS_ON pin from the V. you have at the socket present as STB ( (BU5V) : 4.95V ) then this will be stand alone. runing the PCB with out LED BL and MB

Is it safe to just jump PD15 to PD-14? or must have a ??ohm resistor in between?

[Diah]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

Is it safe to just jump PD15 to PD-14? or must have a ??ohm resistor in between?

R considered just in case people missed the pin No. so ab to you.

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

R considered just in case people missed the pin No. so ab to you.

Jumped PD-15 to PD-14:
This is power supply stand-alone, without any connection:
PD-1 (PNL12V) : 0.01V
PD-2 (PNL12V) : 0.01V
PD-3 (SGRN) : 0.01V
PD-4 (SGRN) : 0.01V
PD-5 (UR13.2V) : 13.05V
PD-6 (UR13.2V) : 13.05V
PD-7 (UR13.2V) : 13.05V
PD-8 (UR13.2V) : 13.05V
PD-9 (SGRN) : 0.01V
PD-10 (SGRN) : 0.01V
PD-11 (SGRN) : 0.01V
PD-12 (SGRN) : 0.01V
PD-13 (AC_DET) : 3.27V
PD-14 (PS_ON) : 4.95V
PD-15 (BU5V) : 4.95V
PD-16 (PNL_POW) : 0.11V
PD-17 (NC) : 0V
PD-18 (NC) : 0V
PD-19 (DIMMER) : 0V
PD-20 (NC) : 0V
PD-21 (OFL) : 0V
PD-22 (ERROR) : 0.12V
PD-23 (NC) : 0V
PD-24 (SBY) : 0.1V

Opto-couplers 1: input: 0.99V / output: 2.78V
Opto-couplers 2: input: 1.08V / output: 0.14V
Opto-couplers 3: input: 0.15V / output: 0.84V

[nomoresonys]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

check D7951 diode.

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

check D7951 diode.

D7951 diode:
In-circuit: forward: 318 reverse: 1568
Off-circuit: forward 310 reverse: open

[Diah]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

Jumped PD-15 to PD-14:
This is power supply stand-alone, without any connection:
PD-1 (PNL12V) : 0.01V
PD-2 (PNL12V) : 0.01V
PD-3 (SGRN) : 0.01V
PD-4 (SGRN) : 0.01V
PD-5 (UR13.2V) : 13.05V
PD-6 (UR13.2V) : 13.05V
PD-7 (UR13.2V) : 13.05V
PD-8 (UR13.2V) : 13.05V
PD-9 (SGRN) : 0.01V
PD-10 (SGRN) : 0.01V
PD-11 (SGRN) : 0.01V
PD-12 (SGRN) : 0.01V
PD-13 (AC_DET) : 3.27V
PD-14 (PS_ON) : 4.95V
PD-15 (BU5V) : 4.95V
PD-16 (PNL_POW) : 0.11V
PD-17 (NC) : 0V
PD-18 (NC) : 0V
PD-19 (DIMMER) : 0V
PD-20 (NC) : 0V
PD-21 (OFL) : 0V
PD-22 (ERROR) : 0.12V
PD-23 (NC) : 0V
PD-24 (SBY) : 0.1V

Opto-couplers 1: input: 0.99V / output: 2.78V
Opto-couplers 2: input: 1.08V / output: 0.14V
Opto-couplers 3: input: 0.15V / output: 0.84V

good so we do have 13V. ur PCB okay... now you add another jumper use R1K from pin 15 to pin 16 PNL_POW to turn on PNL12V.

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

good so we do have 13V. ur PCB okay... now you add another jumper use R1K from pin 15 to pin 16 PNL_POW to turn on PNL12V.

Alright!
But got to go scout for the R1K resistor from the stashed PCBs. It's passed midnight, will do this tomorrow morning and report back.

Thank you.

[nomoresonys]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

better scout 2 more then, you will need to jump ps-on, pnl-pow, ofl and dimmer to bu5v, then you can see if the backlights come on and stay on, if they do then your backlights and powerboard are ok.

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

better scout 2 more then, you will need to jump ps-on, pnl-pow, ofl and dimmer to bu5v, then you can see if the backlights come on and stay on, if they do then your backlights and powerboard are ok.

Jumped PD-15 to PD-14; and PD-16, PD-19, and PD-21, each with a 800ohm resistor:
This is power supply stand-alone, without any connection:
PD-1 (PNL12V) : 11.92V
PD-2 (PNL12V) : 11.92V
PD-3 (SGRN) : 0.02V
PD-4 (SGRN) : 0.02V
PD-5 (UR13.2V) : 13.05V
PD-6 (UR13.2V) : 13.05V
PD-7 (UR13.2V) : 13.05V
PD-8 (UR13.2V) : 13.05V
PD-9 (SGRN) : 0V
PD-10 (SGRN) : 0V
PD-11 (SGRN) : 0V
PD-12 (SGRN) : 0V
PD-13 (AC_DET) : 3.27V
PD-14 (PS_ON) : 4.95V
PD-15 (BU5V) : 4.95V
PD-16 (PNL_POW) : 4.58V
PD-17 (NC) : 0.04V
PD-18 (NC) : 0.04V
PD-19 (DIMMER) : 1.34V
PD-20 (NC) : 0.04V
PD-21 (OFL) : 1.64V
PD-22 (ERROR) : 0.12V
PD-23 (NC) : 0.04V
PD-24 (SBY) : 0.01V

Opto-couplers 1: input: 0.99V / output: 2.78V
Opto-couplers 2: input: 1.08V / output: 0.14V
Opto-couplers 3: input: 0.15V / output: 0.84V

Mounted PS back onto TV, connected LED backlights, powered-on, but nothing happens - no backlight on TV...

A quick checked - the big cap shows 403Vdv but all the transformers above it shows no voltages in all the output pins... With a LED tester - all the 14 led strips are mostly 175V, with 2-3 showing 173-174V.

What/where else to check?

[Diah]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

yours PCB are fine dont touch it any more.. put it back and show us whole photo of TV back showing how boards connected and photos on your MB and it chassis lable.

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

yours PCB are fine dont touch it any more.. put it back and show us whole photo of TV back showing how boards connected and photos on your MB and it chassis lable.

Please see attached - TV Back, MB, and Chasis Label.

[Diah]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

is this DIY TV ??? why the socket which it should be at MB go down and had DIY cable ..

you should put every things back as opriginal so you can troubleshooting the MB .

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

is this DIY TV ??? why the socket which it should be at MB go down and had DIY cable ..

This is the same PS board that we're working on to check if it is working, with all the jumped wires to measure the voltages of PD connector. When mounted back onto the TV, I kept the jumped wires to see if the TV backlight comes on when powered up.

MB metal plate cover removed just to show how cables are connected.

You want to see the PS to MB cable connected?

[Diah]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

put every thimngs back as original. and remove load from the MB , mean speaker socket out wifi module if you have also out.. turn on and check if you have the 13V at start up.. if no you need MB in case your BL are 100% fine.

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

put every thimngs back as original. and remove load from the MB , mean speaker socket out wifi module if you have also out.. turn on and check if you have the 13V at start up.. if no you need MB in case your BL are 100% fine.

With only PD cable connected - now the power led indicator flashing 2x red, constantly.
I connected the display & power cables to T-con board - same flashing 2x red light.

I was curious about LED tester show mostly 175V per strip but I didn't see any led light at the back of TV. So I test again and watch the TV screen - no visible light also even though LED Tester show 175V. Possible to have all the led strips shorted?

[beetle1303]

Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

With only PD connector on MB, only PD-15 showing 4.96V (and not fluctuating), the rests are 0V... I connected Display and power to T-Con, same readings on PD connector, and everything connected back to MB, still same readings - only PD-15 has 4.96V.

Seems like not connect to MB at all? Or MB is dead?