Vizio P502UI-B1E No Picture Flashing Standby Light

[Gadjet]

Ok so when I plug it in the standby light comes on and goes out. Then I hit the power button and it does the same thing but I can see the light from the optical port and the lights are flashing on the network port when I plug in an ethernet cord. After about 5 mins the stand-by light flashes like 23-24 times then the power goes off. I don't see the optical port lit up any more or the network port. I've got a new power supply and changed the eeprom on the Main Board still no change.

[ziekal]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

I have Same tv and same problem. Any luck?

[nomoresonys]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

Could be backlight failure, check the numerous posts/threads on backlight testing.

[Nick's Tvs]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

This is a common issue, we see this TV come into our shop often and its always the main board with those symptoms. Do not buy the eeprom from shopjimmy or other retailers, there is no kit that will fix this. We have tried them all. So far we have been having to replace the entire board every time.

[Gadjet]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

Thanks, @Nick's tvs, Yeah I had tried the eeprom, haven't been able to find a board in stock anywhere. encompass parts is the only one that has it in stock but the price is beyond ridiculous. I've had a stock alert set at shop jimmy since Aug 9th, 2018. Do you have any suggestions on where I can get one?

[Cwood]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

Has anyone figured out the problem with this tv? I've changed the eprom on the main board, purchased a new main board and a new driver board and still no change. Any help would be greatly appreciated.

[Gadjet]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

@cwood where did you find a board? I can't find one in stock anywhere!

[JDMRpr78]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

Raising an old thread but I was just gifted this same tv with the same symptoms. I have confirmed the set is not running and there is no picture on the screen when using a flashlight so definitely not the backlights. I never have a 5v reference at any time. I’m leaning towards a bad power supply but wanted to see if there have been any further developments with this particular set?

[R_J]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

You should have +12 volts across C9107 or C9108, if not the fault is likely on the primary side, Check the voltage across C9803, it should be at least 160vdc.
If you don't have any voltage, check for open fuse
If you have 160vdc, check for a shorted Q9101 and open R9101

[JDMRpr78]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

Ok I do have 12v at c9107/c9108

I also get 171.6 across c9803

R9101 is good with 0.06 ohms
Q9101 between collector & emitter I have 4ohms
Between collector & base shorted
Between emitter & base shorted

Now what?

[R_J]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

You have +12v, good, that supplies IC9301,pin 2, and should output +5 volts on pin7 (or across C9309)
This should be the +5 volt standby for the main, CN9101 or CN9102 pins 15 & 16 [jumper wire J945]
If you have +5 volts going to the main, check if have PS_ON (CN9101 pin3) [Jumper wire J943]. This voltage should change when the power button is pressed, if it does'nt I suspect a main board issue, likely eeprom

If you have 5 volts on J945 and need to test the power supply, disconnect the plug between the main board and and power supply and connect a 1K resistor between J945 & J 943, that should turn on the power supply and give you +12 volts on J944

[JDMRpr78]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

I have left the house now but will check when I return. I did forget to say I have already gotten an eeprom and replaced it. No change in set from before replacement.

Thank you for the help thus far.

[JDMRpr78]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

You have +12v, good, that supplies IC9301,pin 2, and should output +5 volts on pin7 (or across C9309)
This should be the +5 volt standby for the main, CN9101 or CN9102 pins 15 & 16 [jumper wire J945]
If you have +5 volts going to the main, check if have PS_ON (CN9101 pin3) [Jumper wire J943]. This voltage should change when the power button is pressed, if it does'nt I suspect a main board issue, likely eeprom

If you have 5 volts on J945 and need to test the power supply, disconnect the plug between the main board and and power supply and connect a 1K resistor between J945 & J 943, that should turn on the power supply and give you +12 volts on J944

I cannot find ic9301, I have found ic9103. I did look on the back and closest I found was ic9201.

Ok so pin 15 & 16 for cn9101/cn9102 are blank(no pins in the harness either). J945 does not have 5v either. Not even when I attempt to power on the set.

[JDMRpr78]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

Here are photos of my boards

[budwich]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

I cannot find ic9301, I have found ic9103. I did look on the back and closest I found was ic9201.

Ok so pin 15 & 16 for cn9101/cn9102 are blank(no pins in the harness either). J945 does not have 5v either. Not even when I attempt to power on the set.

where are looking for the 5v? As you indicate and show in the pictures, 5v is not sent from the power board as there is no wiring.

[R_J]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

After a closer look at the SJ picture, this board does not use 5volts for standby and uses 12V volts instead, Are there any wires going to the +12V on CN9202?
Its hard to trace the pictures sometimes, for example, this board does not use +12VA as well (L9102 not installed)

So this board must use +12 volts for standby to the main board, I suspect the main board has the +5 volt regulators etc
Check on your main board and see if you have any voltage on FB703 (next to CN701)

Also are you sure you got the correct eeprom for your board? Which one did you order?

[JDMRpr78]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

After a closer look at the SJ picture, this board does not use 5volts for standby and uses 12V volts instead, Are there any wires going to the +12V on CN9202?
Its hard to trace the pictures sometimes, for example, this board does not use +12VA as well (L9102 not installed)

So this board must use +12 volts for standby to the main board, I suspect the main board has the +5 volt regulators etc
Check on your main board and see if you have any voltage on FB703 (next to CN701)

Also are you sure you got the correct eeprom for your board? Which one did you order?

Yes I matched the information exactly to the one I purchased. I got it on eBay from Mtronix. Here is a link https://rover.ebay.com/rover/0/0/0?m...2F163209003570

It matches exactly with the board I have. Of course there is always the possibility that the eeprom installed is no good. It wouldn't be the first time I've had that happen to me.

I'll get the rest of the readings in just a second. Thank you again.

[JDMRpr78]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

Cn9202 is the 14 pin single row connector pictured with only 4 wires (2 peach/2brown). Brown is ground and peach is +24VA

I assume you meant cn9101/cn9102 which does have 6 terminals labeled as 12v. Only 4 of them have a wire in them. The two without are the +12VA. All four of them do have 12v.

FB703 does have 12 volts on both sides of it. So if it uses 12v for standby then maybe I do have a bad eeprom, though I read bad stuff about the main boards on these TV's all the time.

Any way to tell if my eeprom is any good?

[budwich]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

If you read / believe Nicktv's comment on the eeprom replacement, it doesn't sound good about the main board.

You might want to check the main board a bit more in terms of the 12v in going to some of the IC's and look to see if any "pop" as voltage regulators for some lower voltages like 5v therein. Maybe one of them is not quite up to its work.

another question, do you have sound from any inputs?

one other dumb question... what voltage do you have on the PS-ON at the power board.

[JDMRpr78]

Re: Vizio P502UI-B1E No Picture Flashing Standby Light

I can’t get the set to come on at all other than the standby light coming on and fading away. Nothing at all appears.

I have about 80mV with the set off, 2.875V when I hit the power button.