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**Diah** · 04-22-2022, 12:20 AM

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

Originally posted by beetle1303 View Post

But I am tester each of the 14 strips individually - should be able to lit up the 30 leds in it as I have tested it on older 30-led strip.
I will retry in total darkness and see if what happen.

*the link to MB you provide is quite expensive... I am searching of cheaper ones from China but they seems to be of different models.

from the PCB design of LED section. it sound LED are 5-6V. so 30x6 180V. beside the ampere, tester show you 174V. and i do know of sure its very limited with currents.

**nomoresonys** · 04-22-2022, 03:30 AM

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

worth a try, from what I gather the lc and le just might be interchangeable, if it don't work you could resell it I guess.

**nomoresonys** · 04-22-2022, 03:33 AM

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

Originally posted by Diah View Post

from the PCB design of LED section. it sound LED are 5-6V. so 30x6 180V. beside the ampere, tester show you 174V. and i do know of sure its very limited with currents.

so according to that, it's looking like maybe one bad led per string then?

**Diah** · 04-22-2022, 03:39 AM

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

Originally posted by nomoresonys View Post

so according to that, it's looking like maybe one bad led per string then?

i don't think so, because he had MB issue, and this sharp when you force it on as he did.. will clear error at LED if exist and light them up even for short time or long time with just few strips.

**nomoresonys** · 04-22-2022, 03:42 AM

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

ok, yeah I thought there should be some sort of flash but wasn't sure.

**beetle1303** · 04-22-2022, 09:58 AM

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

I went ahead to order a closest model MB for replacement, arriving in 10-20 days. Hopefully it will turn on the PD pins for backlight, and fire-up all the led strips.
Figure crossed!

**beetle1303** · 04-22-2022, 10:05 AM

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

I found this page from one of the link provided interesting and will be very useful if the replacement MB doesn't fire-up the backlight.

Attached Files

**Diah** · 04-22-2022, 10:24 AM

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

Originally posted by beetle1303 View Post

I found this page from one of the link provided interesting and will be very useful if the replacement MB doesn't fire-up the backlight.

all these are working at your PCB other wise you will not have 13 / 12V. only we didnt test the BL circuit because for me i cant figure it out where are the signal to turn it on,,, so i wrote let the MB do the job first,

can you follow the pathof OFL line and dimming one too from downside the PCB?

**lotas** · 04-22-2022, 11:01 AM

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

OFL is DIM, Try to run a PSU with backlight without a motherboard, there are 3 or 4 signals for on, 1kΩ resistor and 5v duty. (OFL for backlight too)

Attached Files

**Diah** · 04-22-2022, 12:06 PM

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

so now it clear.
to complete pcb to run as standalone

PD-15 (BU5V) ----- 14 PS_ON ( turn on UR13.2V )
PD-15 (BU5V) ----- 16 PNL_POW (turn on PNL12V )
PD-15 (BU5V) ----- 24 (STB) ( turn on BL_ on ) IC7700
------------------------------------------------------
PD-21 (OFL) = DIM (low / high )

**beetle1303** · 04-23-2022, 04:36 AM

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

Originally posted by Diah View Post

so now it clear.
to complete pcb to run as standalone

PD-15 (BU5V) ----- 14 PS_ON ( turn on UR13.2V )
PD-15 (BU5V) ----- 16 PNL_POW (turn on PNL12V )
PD-15 (BU5V) ----- 24 (STB) ( turn on BL_ on ) IC7700
------------------------------------------------------
PD-21 (OFL) = DIM (low / high )

With jumper wires on:
PD-15 (BU5V) ----- 14 PS_ON ( turn on UR13.2V )
PD-15 (BU5V) ----- 16 PNL_POW (turn on PNL12V )
PD-15 (BU5V) ----- 24 (STB) ( turn on BL_ on ) IC7700

PD Connector:
PD-1 (PNL12V) : 11.92V
PD-2 (PNL12V) : 11.92V
PD-3 (SGRN) : 0V
PD-4 (SGRN) : 0V
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) : 0V
PD-20 (NC) : 0.04V
PD-21 (OFL) : 0.14V
PD-22 (ERROR) : 0V
PD-23 (NC) : 0.04V
PD-24 (SBY) : 4.3V

But, still no backlight on...

I measured again the big cap all has 400V, but the feed to the 2 big transformers input pins all still showing 0V..
I did a bit of guess tracing - is transformer T7703 input voltage coming from the secondary side to provide output voltage in the primary side to feed the gate of the transistor Q7700 & Q7701? I traced the 400V from caps to left pin of Q7700, but no voltage on its center pin.

Attached Files

**lotas** · 04-23-2022, 05:09 AM

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

The PD-21 (OFL) must also be fed through a 1 kOm 5v resistor.
Yes, and all command pins must be supplied with 5v (standbay) through 1 kOm resistors.

**nomoresonys** · 04-23-2022, 06:31 AM

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

I think you need to hook up the dim too, try it both ways maybe.

**nomoresonys** · 04-23-2022, 06:33 AM

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

so 14, 16, 24, ofl, if no joy hook up dimm also.

**Diah** · 04-23-2022, 06:45 AM

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

OFL and dimmer should be feed too from PD-15 (BU5V) .
use 1K R to avoid the mosfet of BL circuit overload.

**beetle1303** · 04-23-2022, 06:45 AM

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

Originally posted by lotas View Post

The PD-21 (OFL) must also be fed through a 1 kOm 5v resistor.
Yes, and all command pins must be supplied with 5v (standbay) through 1 kOm resistors.

ith jumper wires on:
PD-15 (BU5V) ----- 14 PS_ON ( turn on UR13.2V )
PD-15 (BU5V) ----- 16 PNL_POW (turn on PNL12V )
PD-15 (BU5V) ----- 24 (STB) ( turn on BL_ on ) IC7700
*PD-15 (BU5V) ----- 21 OFL*

PD Connector:
PD-1 (PNL12V) : 11.92V
PD-2 (PNL12V) : 11.92V
PD-3 (SGRN) : 0V
PD-4 (SGRN) : 0V
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) : 0V
PD-20 (NC) : 0.04V
*PD-21 (OFL) : 0V*
PD-22 (ERROR) : 0V
PD-23 (NC) : 0.04V
PD-24 (SBY) : 4.3V

Now the screen Flash in split second then off.

*BTW all jump wire with ~850ohm resistor - it this OK?

**nomoresonys** · 04-23-2022, 06:51 AM

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

ok, then i think it is what was suspected bad led/s.

**nomoresonys** · 04-23-2022, 06:54 AM

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

850 should be fine.

**Diah** · 04-23-2022, 06:55 AM

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

you forget dimmer

**nomoresonys** · 04-23-2022, 06:55 AM

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

add one on dimmer and see what you get. You beat me by a second Diah, that's what I get for using too many words.

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

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