westinghouse DWM551Y1 no power

[taft1957]

Re: westinghouse DWM551Y1 no power

With the voltage so high I was afraid to hook it back up. I thought it was just suppose to be 100 volts/ I will get you some pictures.

[taft1957]

Re: westinghouse DWM551Y1 no power

here is a new development on this repair attempt. I got some guts, plus my curiosity got the best of me, and I installed the main board and opened the backlight panel. I jumped 5 volts to power on, and I couldn't find a backlight on, on the main board. There was another PS ON So, I jumped that. On plugging in the power. It takes about 5 seconds, all backlights light extremely bright for 2 seconds, and then they go off. When you power off, they blink on once more for a secoond. I took some more picture, and a short video. I hve never attached a video before, but I will try.

[taft1957]

Re: westinghouse DWM551Y1 no power

Well I just attempted a upload of a avi file and it failed. My post seemed to fail also. I will try again.

[taft1957]

Re: westinghouse DWM551Y1 no power

well second attempt on upload the video failed.

[budm]

Re: westinghouse DWM551Y1 no power

Too blurry for my eyes.

[taft1957]

Re: westinghouse DWM551Y1 no power

Just another picture

[taft1957]

Re: westinghouse DWM551Y1 no power

I jumped 5 volts to PS ON, and I jumped 5 volts to PS on at the main board. I couldn't find a backlight ON The backlight now lights for 2 seconds and goes off, all led's light extremely bright. Then when you unplug the tv they light again for just a second.

[budm]

Re: westinghouse DWM551Y1 no power

I jumped 5 volts to PS ON, and I jumped 5 volts to PS on at the main board. I couldn't find a backlight ON The backlight now lights for 2 seconds and goes off, all led's light extremely bright. Then when you unplug the tv they light again for just a second.

I do not get what you are doing, you put the jumper between 5VSTBY and the PS-ON at two places? How did you figure out which pin is the PS-ON? I do not see the pin labels on the top side of the power supply board.
Can you show good clear pictures of the bottom side of the power board where the connectors are, may be the labels for the pin functions are on the bottom side of the power supply board.

[taft1957]

Re: westinghouse DWM551Y1 no power

On the power supply there is a label draw on the board right next to the connector it says that identifies power supply on pin, It says PS ON. I run small wire from 5 volts standby to PS ON and it turns on the power supply. On most sets there is also a BL ON blacklight on, and I usually jump 12 volts to BL ON Just did it on a set today. If the backlight comes on, it confirms you need to replace the main board. However, this damn set has been anything but the norm. On the main board there is no pin labeled BL ON So I am confused. However there is another PS ON Maybe it is a mistake. Maybe it was suppose to read BL ON because when I jumped it, the set went from dead to the backlight coming on for 2 seconds. However, it is shutting off, and it is extremely bright. I am now asking myself is this a main board problem, or do I have shorted LED's on the backlight panel. I am trying to upload a short video. So you can see it.

[taft1957]

Re: westinghouse DWM551Y1 no power

Here is the video.

[taft1957]

Re: westinghouse DWM551Y1 no power

well it says invalid file. not sure what I am doing wrong.

[taft1957]

Re: westinghouse DWM551Y1 no power

As I said earlier in this thread. That voltage on led+ seems to high and unsteady. I leds when they do come on are extremely bright as if the voltage is to high, triggering some type of shutdown. Main board, or LED panel? Or some regulator failing?

[CapLeaker]

Re: westinghouse DWM551Y1 no power

2 things:

You do NOT jumper BLon to 12V DC! You use same STBY 5V as PSon through a 1k resistor.

Second: Now since the backlight actually is coming on (even if it is a short time), I'd be looking at the LED's itself first! The PSU is shutting it down for a reason.

[taft1957]

Re: westinghouse DWM551Y1 no power

What do you need the 1K resister for? One of my tv's that I used to play around with, I just soldered the pins STBY and PS ON. soldered them together Then on the main board I soldered the pins 12 volts to BL ON, soldered them together. I used that tv for years. Why wouldn't it have shorted out? I remember I use to use the resister, and then one day I just forgot, and nothing bad happened, so I just figured it didn't matter that much. In both cases you basically just bypassing a switch, weather your on the power supply, or the main board. Isn't that right? Granted I don't know a lot of theory, or even understand a lot of theory. Just learned by messing around and watching you tube and reading. Use to just jump a relay back in the picture tube tv days. So, I guess I won't do the 12 volt to BL ON anymore. I watched a video on the same symptom. The guys backlight would shut off just like mine. However, several of his were not lighting. He found shorted LED's However, all of mine are lighting. Would a LED light if it was shorted? can you post video's on this site? what file format works?

[taft1957]

Re: westinghouse DWM551Y1 no power

I don't want you to think I am a complete idiot. I did go to college for electronics for two years, Yes at one time I studied theory. However, at the college I went to they never applied the theory to any real life equipment. So many times now you can't get schematics or flow charts. I still use my finger as a temperature gauge. LOL

[budm]

Re: westinghouse DWM551Y1 no power

On the power supply there is a label draw on the board right next to the connector it says that identifies power supply on pin, It says PS ON. I run small wire from 5 volts standby to PS ON and it turns on the power supply. On most sets there is also a BL ON blacklight on, and I usually jump 12 volts to BL ON Just did it on a set today. If the backlight comes on, it confirms you need to replace the main board. However, this damn set has been anything but the norm. On the main board there is no pin labeled BL ON So I am confused. However there is another PS ON Maybe it is a mistake. Maybe it was suppose to read BL ON because when I jumped it, the set went from dead to the backlight coming on for 2 seconds. However, it is shutting off, and it is extremely bright. I am now asking myself is this a main board problem, or do I have shorted LED's on the backlight panel. I am trying to upload a short video. So you can see it.

That is why I request the pictures of the bottom side of the board also since as you can seem they did put pin labels for the LED connectors on the bottom side side of the board, so I need to see good clear pictures of the board especially around the connectors.
As you can see the pictures from SJ, the bottom side of the board has insulation sheet so I cannot see if there are any labels on the bottom side of the board for the CN201 connector.

[dick_barton]

Re: westinghouse DWM551Y1 no power

taft1957
Take a really simple case of where P_ON or BL_On are shorted to ground.

With the connection of a 1K resistor you will not have placed a short circuit on the +5V standby when connecting to either P_On or BL_On because the 1K will limit the short circuit current to 5mA.

However without a resistor in place you have just shorted out your 5V stby supply and may have yet another repair to complete.

It's just better to be safe than sorry.

[budm]

Re: westinghouse DWM551Y1 no power

Another thing you have to watch out for when using the direct connection between the Voltage source pin to the command pin, you must disconnect the cable back to the main board first since the switched transistor will normally be FULLY ON (Transistor is in Saturated mode) to keep the command line output at LOW state (basically shorted to GND), if you connect the force on Voltage source without disconnecting the cable to the main board you can damage that switched transistor on the main board, using resistor is also help limit the current in case the connection is made wrong. I ALWAYS use the resistors.
See the schematic on how the switched Transistors are used as the switches on the main board for PS-ON, BL-ON.

[taft1957]

Re: westinghouse DWM551Y1 no power

Thank you for taking the time to educate me on that subject. I guess I have got very lucky in the past. i won't do that anymore. One of those pictures was the back corner. I guess the quality is still to poor. What do you use to take pictures with? Where do I go from here?

[CapLeaker]

Re: westinghouse DWM551Y1 no power

Depending what it is, I am using a DSLR or my iPad.