Westinghouse 55" - mostly dead

[dskall]

Re: Westinghouse 55" - mostly dead

Is ps_on 4.7v in standby?

[dskall]

Re: Westinghouse 55" - mostly dead

So with the mainboard disconnected you have all the following voltages on the power supply.
+5VSTB, +5V, +12V, +24V
PS/ON is 4.7V and does not change and BL/ON is 0.5V

If you jumper +5VSTB using a 1K resistor to BL/ON does that bring up the backlights.

Not sure but seems he has voltage at ps_on in standby so would have to pull ps_on low to force power on.

[dick_barton]

Re: Westinghouse 55" - mostly dead

My thought was if all the supplies are up then the only voltage missing is BL/ON

[Rexbot]

Re: Westinghouse 55" - mostly dead

Westinghouse 55 UHD 4k Fixed!!!

My tv would not turn on, the red light was on.

Here is how I fixed it.
1.) I baked the mainboard in the oven at 250F for 10 minutes.

2.) I baked the smaller board at 250F for 10 minutes

3.) I cut a hole in the back panel to install a 4 inch PC Case Fan, and wired it to run on usb. Make the hole right above the grey heatsink on the mainboard.

4.) I replaced my power supply mainboard because it was just $80 shipped. There was nothing wrong with my old power supply.

It has been running smoothly since I fixed it.

What is the problem? The grey heatsink is overheating on the mainboard causing weak connections to break. They probably didn't put enough solder on the mainboard.

Note: baking the mainboard may require a higher temperature if baking it at 250F does not work. I tried 300F for 7 minutes and it worked like a charm.

[Rexbot]

Re: Westinghouse 55" - mostly dead

To bake the mainboard, make sure you wrap all the plastic bits in a few layers of tinfoil.

[dskall]

Re: Westinghouse 55" - mostly dead

Westinghouse 55 UHD 4k Fixed!!!

My tv would not turn on, the red light was on.

Here is how I fixed it.
1.) I baked the mainboard in the oven at 250F for 10 minutes.

2.) I baked the smaller board at 250F for 10 minutes

3.) I cut a hole in the back panel to install a 4 inch PC Case Fan, and wired it to run on usb. Make the hole right above the grey heatsink on the mainboard.

4.) I replaced my power supply mainboard because it was just $80 shipped. There was nothing wrong with my old power supply.

It has been running smoothly since I fixed it.

What is the problem? The grey heatsink is overheating on the mainboard causing weak connections to break. They probably didn't put enough solder on the mainboard.

Note: baking the mainboard may require a higher temperature if baking it at 250F does not work. I tried 300F for 7 minutes and it worked like a charm.

Maybe you can keep us updated on how long repair lasts. Heating at such low temp is not reconnecting bad solder connections since it takes around 370f to melt leaded solder and lead free even higher.

[AndrewD]

Re: Westinghouse 55" - mostly dead

I have a cheap junky Westinghouse WD55UW4620 TV in my shop. (Pretty sure these are Wal Mart/Best Buy specials...)

Problem: Won't power on. Red power LED on constantly, power button/remote does nothing. No variation/indication when pressing power button.

All boards look good, no popped caps, nothing looks burnt.

Checked all power board voltages (between power brd & main brd) - All appear to be within reasonable values as per the board markings. Nothing missing, nothing too far out of whack. No voltage changes anywhere when pressing power button.

I suspect the main board (only because all the power board voltages seem right...) - Disconnecting power board connector Con2 that is connected to connector J6 on the main board does NOT turn on backlights like most LCDs I've repaired but I can't locate a service manual for this model so I'm not sure if it's supposed to on this model.

SO far I've tracked down a replacement main board from one of my regular sources for around $120.00. Before I spend money for nothing...

Anyone have any good tips on confirming a little more clearly whether it's more likely to be a problem with the main or the pwr board? I have all the necessary test equipment, including a scope but without a service manual/schematic the test equipment is kinda useless.

TV: Westinghouse WD55UW4620
Main board is a CV6488H-A-20.
Power board is aAY155D-45F12

I'm an experienced tech - Any tips/advice (or a link to the service manual) would be gratefully accepted.

Hey Art_Dodger,

Did you ever find a solution to the WD55UW4620? I've unfortunately got one doing the exact same thing and just trying to get as much information as possible before throwing parts at it.

Thanks!

Andrew

[AndrewD]

Re: Westinghouse 55" - mostly dead

Hey Art_Dodger,

Did you ever find a solution to the WD55UW4620? I've unfortunately got one doing the exact same thing and just trying to get as much information as possible before throwing parts at it.

Thanks!

Andrew

In case it helps anyone in the future, I had the exact same problem as OP and I ended up changing the main board and that fixed the problem! If your in Canada and want to avoid ordering from the US, I used UsefulParts, they were cheap, quick and Canadian. Here's where I found it: http://www.usefulparts.com/index.php...rd=WD55UW4620+

[boxtel964]

I have a cheap junky Westinghouse WD55UW4620 TV in my shop. (Pretty sure these are Wal Mart/Best Buy specials...)

Problem: Won't power on. Red power LED on constantly, power button/remote does nothing. No variation/indication when pressing power button.

All boards look good, no popped caps, nothing looks burnt.

Checked all power board voltages (between power brd & main brd) - All appear to be within reasonable values as per the board markings. Nothing missing, nothing too far out of whack. No voltage changes anywhere when pressing power button.

I suspect the main board (only because all the power board voltages seem right...) - Disconnecting power board connector Con2 that is connected to connector J6 on the main board does NOT turn on backlights like most LCDs I've repaired but I can't locate a service manual for this model so I'm not sure if it's supposed to on this model.

SO far I've tracked down a replacement main board from one of my regular sources for around $120.00. Before I spend money for nothing...

Anyone have any good tips on confirming a little more clearly whether it's more likely to be a problem with the main or the pwr board? I have all the necessary test equipment, including a scope but without a service manual/schematic the test equipment is kinda useless.

TV: Westinghouse WD55UW4620
Main board is a CV6488H-A-20.
Power board is aAY155D-45F12

I'm an experienced tech - Any tips/advice (or a link to the service manual) would be gratefully accepted.

My TV is same, problem is same, I tested all voltage like these:

ON POWER BOARD PINS

+5VSB 5.13V
PS/ON 4.72V
+5V 5.13V
+12V 12.59V
+24V 21.87V
bl/ON 49.5mV
ADJ 106.3mV

ON MAIN BOARD J8 KEY & IR BOARD CONNECTOR PINS

TOP TO IR BOARD I HAVE +5.11V AND 1.697V
DOWN TO PUSHBUTTONS I HAVE +3.29V, THEY WOULD DROP FROM O TO 0.8V WHEN I PUSHED DIFFERENT PUSH BUTTONS.

PLEASE TELL ME WHERE IS THE PROBLEM, POWER BOARD OR MAIN BOARD. THANKS.

[vinceroger69]

Re: Westinghouse 55" - mostly dead

bl on is low at 49.5mv in not sure what the adj pin should read, there does seem too be issues with these main boards after reading a few threads.budm may see this thread and advise on more possible tests

[budm]

Re: Westinghouse 55" - mostly dead

My TV is same, problem is same, I tested all voltage like these:

ON POWER BOARD PINS

+5VSB 5.13V
PS/ON 4.72V
+5V 5.13V
+12V 12.59V
+24V 21.87V
bl/ON 49.5mV
ADJ 106.3mV

ON MAIN BOARD J8 KEY & IR BOARD CONNECTOR PINS

TOP TO IR BOARD I HAVE +5.11V AND 1.697V
DOWN TO PUSHBUTTONS I HAVE +3.29V, THEY WOULD DROP FROM O TO 0.8V WHEN I PUSHED DIFFERENT PUSH BUTTONS.

PLEASE TELL ME WHERE IS THE PROBLEM, POWER BOARD OR MAIN BOARD. THANKS.

Are those Voltage readings with all the connectors in place? It it is then your main board is not sending out the BL-ON or Dim control signals.

[boxtel964]

Re: Westinghouse 55" - mostly dead

I just wonder the power board +24v out put 21.87v stable normal or problem. Thanks.

[nomoresonys]

Re: Westinghouse 55" - mostly dead

See link in post #28, be sure to match those first 7 numbers if you get one.

[boxtel964]

Re: Westinghouse 55" - mostly dead

So it should be main board problem, right?

[nomoresonys]

Re: Westinghouse 55" - mostly dead

https://www.youtube.com/watch?v=jj6quLUjULs
Video explaining how the boards interact with each other.

[nomoresonys]

Re: Westinghouse 55" - mostly dead

Sure looks like it, as they said in post 30 and 31, bl_on which comes from the mainboard is too low. Not sure about your 21 v, but your not getting enough bl_on voltage to turn the backlights on.

[vinceroger69]

Re: Westinghouse 55" - mostly dead

I just wonder the power board +24v out put 21.87v stable normal or problem. Thanks.

if the 24v does the audio some times ive noticed reading the threads it can read low regarding the issue power supply or motherboard at fault after reading various posts it does seem that the main board is probably at fault but obviously no guarantee as your set could have one or more faults.

[budm]

Re: Westinghouse 55" - mostly dead

21V is not the real problem right now, missing the BL-ON and the Dim are the problem from the main board. BL-ON does not control how high the 24V will be, BL-ON is the signal to turn on the inverter circuits. O-SON signal turn the 12v 24V power supply on and off and it does not control the output Voltage level.
Just think of the control signal as a switch you use to turn the lamp on or off, but the brightness of the lamp will depend on the AC Voltage level feeding the lamp not the switch.
So if the PS-ON is > 2 ~2.5VDC that will be equal to switch is on, so if the PS-ON is 5V that will not make the 24V power supply to put out more then 24V.
You can force on the power supply and inverter circuits using pull-up resistors.

[nomoresonys]

Re: Westinghouse 55" - mostly dead

21V is not the real problem right now, missing the BL-ON and the Dim are the problem from the main board. BL-ON does not control how high the 24V will be, BL-ON is the signal to turn on the inverter circuits. O-SON signal turn the 12v 24V power supply on and off and it does not control the output Voltage level.
Just think of the control signal as a switch you use to turn the lamp on or off, but the brightness of the lamp will depend on the AC Voltage level feeding the lamp not the switch.
So if the PS-ON is > 2 ~2.5VDC that will be equal to switch is on, so if the PS-ON is 5V that will not make the 24V power supply to put out more then 24V.
You can force on the power supply and inverter circuits using pull-up resistors.

+1 Exactly.

[boxtel964]

Re: Westinghouse 55" - mostly dead

21V is not the real problem right now, missing the BL-ON and the Dim are the problem from the main board. BL-ON does not control how high the 24V will be, BL-ON is the signal to turn on the inverter circuits. O-SON signal turn the 12v 24V power supply on and off and it does not control the output Voltage level.
Just think of the control signal as a switch you use to turn the lamp on or off, but the brightness of the lamp will depend on the AC Voltage level feeding the lamp not the switch.
So if the PS-ON is > 2 ~2.5VDC that will be equal to switch is on, so if the PS-ON is 5V that will not make the 24V power supply to put out more then 24V.
You can force on the power supply and inverter circuits using pull-up resistors.

I see now, I ordered one main board, thanks everybody, we can see what will happen.