Vizio vw37l Amber light only will not power on

[swwww]

Re: Vizio vw37l Amber light only will not power on

Thanks, you guys have been very helpful



Do you have any clarification for your reference to u3 no input voltage tom?

(as it receives essentially no input, it gives no output.) (u3)

so are you are saying no input should not be expected for the conditions ( because of tv not being on) or are you just stating the obvious (no input no output)

Its positioned above the 75ohm output section so i kind of guessed it would not be energized while tv was off??


thanks

[tom66]

Re: Vizio vw37l Amber light only will not power on

When the amber light is on, TV is in standby. This means only supply is (usually) just 5V. The 5V feeds some parts of the main board which are active in standby mode.

That regulator provides regulated power for probably the tuner, audio or video processor when the TV has powered on fully (white.)

If there is a fault with a regulator, usually the TV won't even attempt to power up, so you'll see no voltages there.

[budm]

Re: Vizio vw37l Amber light only will not power on

U3 is fed by the 12v power supply which is off when TV is in standby mode, when TV is turn on the main board will send the PS_ON to turn on the 12v/24v power supply,then you will get the 5V output of that 5V regulator IC

[swwww]

Re: Vizio vw37l Amber light only will not power on

Thats what i was thinking. Thank you for taking the time to help and explain-- I feel I owe ya guys a pint
..
I was trained to component level repair in the us navy about 20 yrs ago but most all of my field experience has been what the navy calls "organizational" level which is board/box/cable/connector with a bunch of signal flow. So its all a bit fuzzy/rusty at best



Ill get u7 swapped and report back...might be a couple days

thanks again

[swwww]

Re: Vizio vw37l Amber light only will not power on

The voltage regulator came in and I put it in today U7. T.V. works 100%!!!!!!! Yay!!!!

Just wanted to extend my thanks to budm, tom66, johnboy1313, Dgtech and retiredcaps for your help and guidance.

You guys are all over this site helping people and I'm pretty sure no one is paying you to do it. Pretty great stuff. From this guy, many thanks!!!!

[martyparish]

Re: Vizio vw37l Amber light only will not power on

It's amazing how many of the Vizios have bad regulators! Good job on the fix!

[retiredcaps]

Re: Vizio vw37l Amber light only will not power on

It's amazing how many of the Vizios have bad regulators! Good job on the fix!

Hence the how to guide with Vizio specifically mentioned inside it. This allows people who search to find the document. Almost 13,000 views since the regulars wrote/contributed to that document.

The days of fixing TVs due to obviously bad caps is probably 10% or less now.

[Shane711]

Re: Vizio vw37l Amber light only will not power on

I got this TV with the Amber light and it will not turn white. The voltage regulators were a little difficult to test this time so I had to refer to budm's post on how to test a voltage regulator "The voltage between the Adjust pin (left pin) and the center pin (Pin2, output) will always be 1.25V". So U2 is reading .88 VDC and U9 is reading 1.5 VDC. Not sure what it means if the voltage is higher but I am about to change these out with new ones.

The output voltage on U9 was reading 1.25 so I thought that was normal and the voltage on U2 was reading 2.25 and I thought that was normal.

So I changed them both out and now the TV is working

U9 is still reading 1.25 and U2 is reading 3.30 so looks like U2 was the only bad one. So back to the quote "The voltage between the Adjust pin (left pin) and the center pin (Pin2, output) will always be 1.25V" Why was the voltage for U9 1.5 VDC? Should it read "will always be 1.25V or higher"?

[budm]

Re: Vizio vw37l Amber light only will not power on

The reading is between ADJ pin 1 and the output pin 2 of the ADJUSTABLE regulator, it is not applied to FIXED output regulator since the pin 1 is GND for the FIXED output regulator.
The output Voltage of the ADJUSTABLE regulator = Voltage at ADJ PIN + 1.25v REF

[Shane711]

Re: Vizio vw37l Amber light only will not power on

Yes, both regulators are the adjustable 1117. Every regulator read 1.25V between Pin 1 & 2 except for U2 & U9 but U9 read 1.5V. U2 read 0.88V and so that was the bad regulator.

Why would U9 read 1.5V and I believe it was not bad but I changed it anyway.

[budm]

Re: Vizio vw37l Amber light only will not power on

The 1.25Vref is very accurate Voltage, The circuit may be able to handle 0.25V higher than expect that is why the circuit may be still operating, but the one with 0.88V, then the output Voltage may be too low to operate.
One IC has 0.88V between ADJ AND adjust, then you add that to the Voltage reading between adj and GND = OUTPUT ON PIN 2 = ???
Second IC has 1.50V between ADJ AND adjust, then you add that to the Voltage reading between adj and GND = OUTPUT ON PIN 2 = ???

[Shane711]

Re: Vizio vw37l Amber light only will not power on

TV is gone, returned to owner. Works perfect.

I though about adding heat sinks to the regulators to keep them from burning up, I will have to experiment with one later and see if they get hot while on.