Sharp LC-46D85U green power light & OPC flashing

[kyho]

I have 46" Sharp TV LC-46D85U, recently it doesn't power on. It gives flashing one power light and OPC light together then flashing one on power light, then repeat the flashing pattern, I checked the forum and the error code for this pattern, it indicates the power supply board is faulty. I am not sure it is the power supply board or other boards. I measured the voltage on the PD connector, I have +2.99 DCV on pin 8 (AC_DET) and +5.01 DCV on pin 12 (BU5V), other pins and LB1, PL, LB2, LA connectors has 0 volt. I removed the power board and connected with BU 5V + 490 ohm resistor to pin 9 (PS_ON). Then I have voltage as 13.5v on pin 1, 2,3,4,5; 0 volt on pin 6; no wire on pin 7; +2.99V on pin 8; +4.8V on pin 9 (PS_ON); 0 volt on pin 10 (PNL_POW); 5.01V on pin 12 (BU5V); no voltage on LB1 and LB2; no volt on pin 1,2(PNL12v), 3,4 of PL connector; but I have 12V on INV12v and 59.7v on INV60v of LA connector.
Not sure the pin 10(PNL_POW) of PD should have any voltage?
Do I have bad power board or main board?
The power board is DPS-277BP, RDENCA295WJQZ.
Please help. Many thanks.

[budm]

Re: Sharp LC-46D85U green power light & OPC flashing

I have 46" Sharp TV LC-46D85U, recently it doesn't power on. It gives flashing one power light and OPC light together then flashing one on power light, then repeat the flashing pattern, I checked the forum and the error code for this pattern, it indicates the power supply board is faulty. I am not sure it is the power supply board or other boards. I measured the voltage on the PD connector, I have +2.99 DCV on pin 8 (AC_DET) and +5.01 DCV on pin 12 (BU5V), other pins and LB1, PL, LB2, LA connectors has 0 volt. I removed the power board and connected with BU 5V + 490 ohm resistor to pin 9 (PS_ON). Then I have voltage as 13.5v on pin 1, 2,3,4,5; 0 volt on pin 6; no wire on pin 7; +2.99V on pin 8; +4.8V on pin 9 (PS_ON); 0 volt on pin 10 (PNL_POW); 5.01V on pin 12 (BU5V); no voltage on LB1 and LB2; no volt on pin 1,2(PNL12v), 3,4 of PL connector; but I have 12V on INV12v and 59.7v on INV60v of LA connector.
Not sure the pin 10(PNL_POW) of PD should have any voltage?
Do I have bad power board or main board?
The power board is DPS-277BP, RDENCA295WJQZ.
Please help. Many thanks.

Please attach good clear pictures of the whole backside of the TV showing all the boards, then good clear straight shots of the whole top and bottom side of the board, the pictures of the power supply board must be clear enough to read the prints on the board so we can see what we are dealing with.

[kyho]

Re: Sharp LC-46D85U green power light & OPC flashing

I shoot couple pictures of the TV, I can upload 3 pictures in one time.
one is the full back view of the Tv, one is the power supply unit and main unit.

[kyho]

Re: Sharp LC-46D85U green power light & OPC flashing

another 1 pictures and reading of all connector.
The volt reading is taking 3 different ways:
1. The power supply unit is with TV
2. The power supply unit is not with TV.
3. The power supply unit is not with TV but pin 9 (PS_ON) and pin 12(BU5V) are connected with a 490ohm resistor.

[budm]

Re: Sharp LC-46D85U green power light & OPC flashing

Please look at this picture of the PD Voltage readings:
https://www.badcaps.net/forum/attach...6&d=1597628463

And then this picture (https://www.badcaps.net/forum/attach...4&d=1597628463) of the PD pin names and number as printed on the board, you can see that pin 1,2, 3, 4 should have 13V when PS-ON is present, you show pin 4 as Zero Volt.

GND pin 8, , your report shows as AC-DET.
AC-DET pin is pin 9, your report shows as PS-ON.
PS-ON is pin 10, your report shows as PNL-POW.
BU5V is pin 11, your report shows as GND.
PNL_PWR are pin 10 and pin 12, your report shows as BU5V.

I suggest you put down pin names and pin numbers on your paper and then verify them with what is printed on the board.
I also need close up pictures of LB2 and LA connectors so I can see what the pin names are.

[kyho]

Re: Sharp LC-46D85U green power light & OPC flashing

I re-write the voltage reading in excel and also enlarge the picture so the printed name can be seen. Just head up, beside the power & OPC light flashing, the power relay clicks on and off when the AC power plugs. And also there has same voltage readings on either the power supply unit with TV or dismounted with TV.
Is this power unit having 12 volt and 5 volt when the TV is on standby.
Thank you for helping me.

[budm]

Re: Sharp LC-46D85U green power light & OPC flashing

Sorry, my mistake, I was looking at the chart for PD1 (not installed), not PD.
TV uses 5V Standby Voltage to keep the main board alive at minimum power.
When PS-ON is present from the main board, the switched 13.5V will come on, at this point this section of the circuit is fine.

Now you will need to add another resistor between PNL_POW and BU5V to turn on the switched PNL12V which should have 12V when PNL_POW is present, the PNL12V is for running the T-CON board, so do that next.

BTW, we are testing the power supply board without cables going to main board in place.
I am going to see if I can locate service manual for this TV.

[budm]

Re: Sharp LC-46D85U green power light & OPC flashing

I found service manual but it does not show error and not much of anything else either, very poor service manual.

[kyho]

Re: Sharp LC-46D85U green power light & OPC flashing

Thank you for the manual but it doesn't have circuit diagram of power unit.
I wonder that the pin 9 (PS_ON) and Pin 10 (PNL_POW) of PL connector should be high when the CPU detects the standby 5 volt pin 12(BU5V).
I will test the voltage at pin1(INV12v) of LA connector as the pin 10 (PNL_POW) connects with pin12 (BU5v).
I would like to understand how this power unit works, as I mentioned that I hear the power relay clicking on / off when the AC plugs in. The relay clicks on then off but the relay doesn't hold on when I press the power button.

[budm]

Re: Sharp LC-46D85U green power light & OPC flashing

Thank you for the manual but it doesn't have circuit diagram of power unit.
I wonder that the pin 9 (PS_ON) and Pin 10 (PNL_POW) of PL connector should be high when the CPU detects the standby 5 volt pin 12(BU5V).
I will test the voltage at pin1(INV12v) of LA connector as the pin 10 (PNL_POW) connects with pin12 (BU5v).
I would like to understand how this power unit works, as I mentioned that I hear the power relay clicking on / off when the AC plugs in. The relay clicks on then off but the relay doesn't hold on when I press the power button.

As I indicated, the service manual is very poor service manual, it does not really gives much needed information.

Right now the main board is not sending out the command signals to turn on the power supply dues to error some where.
The main board sends out the PS-ON (to turn on the switched 13V), PNL_POW (to turn on the switched PNL12V), and BL-ON (which I cannot find that pin on the power supply board yet) is for turning on backlights circuit.

I still need to find out what the 'INV' pins of the LB1 connector are for.

"I will test the voltage at pin1(INV12v) of LA connector as the pin 10 (PNL_POW) connects with pin12 (BU5v)."

You will look for 12V at PNL12V pin of the PL connector when you jump PNL_POW to BU5V
Please read the Basic LCD TV troubleshooting guide.

[budwich]

Re: Sharp LC-46D85U green power light & OPC flashing

I think the set has tubes for backlighting.

[budm]

Re: Sharp LC-46D85U green power light & OPC flashing

I think the set has tubes for backlighting.

It is CCFL backlights, but so far I cannot find error codes and the BL-ON, Dimm command pins.

[kyho]

Re: Sharp LC-46D85U green power light & OPC flashing

yes, the backlit is using tube. I get 12.1volt on pin 1 and 2 (PNL12V) of PL connector when the BU5V connected with PNL_POW.

[budm]

Re: Sharp LC-46D85U green power light & OPC flashing

yes, the backlit is using tube. I get 12.1volt on pin 1 and 2 (PNL12V) of PL connector when the BU5V connected with PNL_POW.

Good, so far two sections of the power supply board are OK.
Next we need to figure out how to force on the backlights, it will need more researching to find out what those LB1 INV pins are for, it will require lots of circuits tracing of the boards.

[kyho]

Re: Sharp LC-46D85U green power light & OPC flashing

Thank you for the information.
I has disconnected all connectors except PD, I can hear the power relay clicking on/off and it still is flashing same error code 1 power + 1 OPC then 1 power when the AC plugs in. And I got as above response when I disconnected the connector one by one except the PD.
I press the power button, the voltage on pin 1 (13.5 signal) of PD, the voltage is jumping to 5 volt then back to 0 volt and the power relay is clicking.
It makes sense the relay should not click on/ off when the AC plugs-in.
Can someone confirm that the power relay should click on/ off when the AC plugs in.

[budwich]

Re: Sharp LC-46D85U green power light & OPC flashing

Some sets "power up" to the last known state when plugged in... be it standby or otherwise. Have you tried a "force on sequence" which sharps typically need to get around an "error state" IF possible to get into a service menu mode state.

[kyho]

Re: Sharp LC-46D85U green power light & OPC flashing

Press Vol (-) + Input and plugs-in AC, then Vol (-) + CH (dn) for awhile to enter Service Mode but nothing happen on Service Mode, still has flashing error code.
Press Vol (+) + CH (DN) and plugs in AC, only the power light on, no flashing error code.
Tried different combinations ( input, menu, CH, Vol) suggest from Sharp's service menu, but nothing is working except the error code flashing.
I traced the INV1 to INV5 on LB1 and LB2, both LB1 and LB2 are passing through power unit, nothing to do with the PSU.
I checked the meaning of error code 2 power + 1 OPC, it indicates that PS_ON failure because of AC_DET : abnormal.
Right now, I am trying to confirm the problem on PSU then I will order PSU replacement.

[budm]

Re: Sharp LC-46D85U green power light & OPC flashing

So LB1/LB2 is just a pass through the power supply board to get the signal form main board to the inverter board.

But I still do not not know which command pins on the power supply board is used to turned on the INV12V and the INV60V power supplies at LA connector for the inverter board to run.

Can I see close up pictures of the inverter board when the LA connector form the power supply board is connected too? I can see the pinout names on the inverter board.
Right now we know that the simulate PS-ON can turn on the power supply but some how when all the cables are back in place, the PS-ON does not go high.
AC - DET signal at this point we do not know if normal incoming AC Voltage AC DET should be HIGH or LOW. The AC-DET is used for checking the incoming AC Voltage level, if the Voltage get too low the TV will draw to much current so it tells main board to stop sending the PS-ON to the power supply.
We can try grounding the AC-DET line on the main board side by disconnecting the AC-DET wire form the connector first then use 100 Ohms resistor to ground the AC-DET pin receiving side of the main board to simulate AC-DET LOW and see if the error code goes away or not.

Sharp TV's that I fixed in the pass, the AC-DET output pin is around 3VDC when incoming AC is normal, <1V when AC is low, so more likely this TV will use the same AC-DET Voltage level.

Where did you get that PS-ON AC-DET error description from for this TV model?
The reason I ask because the same blink codes are not the same for all models

[kyho]

Re: Sharp LC-46D85U green power light & OPC flashing

Good point. As PS_ON is high then LA and LP has voltage as marked so the only signal goes to main unit are BU5V, AC_DET on PD. AC_DET is 2.98VDC which may be in border line of low and high. As you said I will make AC_DET to low (>0) and see what happen. Meanwhile any suggestion where I can purchase used Main unit and PSU, I don't want to pay too much because this TV has been more than 10 year old.