Vizio vw37L (3637-0312-0150 main board) main board repair

[SDeuce]

Common orange to white vizio logo, no sound no picture,. Checked voltages on regulators, all appears to be good but U8.. Its has 1.25 volts on the Input pin, 2.5 on center pin no voltage on output... I had to bad caps on the t- con board, was worried the panel was bad. Rand a jumper from 5v to pos, was able to shine a flashlight into the screen and could see the menu.. My struggle is finding out where I am losing the standby voltage.. And advice would be great.. I know a new main board is $60.. I wanted to fix the board of I could, fully for a learning experiance.. I have fixed 1 other vizio with a regulated.. By the way I did replace the u8 reg. And still have the same problem...

[dskall]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

Need good clear straight on pictures of back of tv with cover off and each board

[SDeuce]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

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[budm]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

"U8.. Its has 1.25 volts on the Input pin, 2.5 on center pin no voltage on output." I think you need to look up the spec sheet of the IC.
Center pin is electrically connect to the center pin and it is an OUTPUT pin!
Left pin can be ADJ or GND depends on if it is fixed or Adjustable.
Right pin is INPUT pin.
So please verify and report the reading of all the pin again, may be the rest of all regulators as well.

"My struggle is finding out where I am losing the standby voltage.." Standby Voltage is present otherwise you will not have that LED indicator lights on the front of the TV.

You should start by providing the DCV of the power supply connector that goes to the main board, make sure to put the pin number and MUST follow by the PIN NAMES, and the DCV for each pin so we easily identify the problems.

BTW,the SMD fuse for the 12V on the main board is OK? You have two SMD fuses on the main board, one is for STBY5V, and one for 12V.

[SDeuce]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

Will do.. The left pin on u8 has 0 volts they are amc1117 adjustable... I'll see if I can get thoses numbers tomorrow..

[budm]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

Let me see the closed up of that U8.

[SDeuce]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

So don't judge my soldering to hard.. I didn't have anything to b get the excess solder off the board.. The picture of u8 is the replacement part.. U2 is the same and had original u8 part number[/URL][/IMG]

[budm]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

So first lest make sure you do not have any solder bridge to the from IC legs to GND by checking the resistance between GND and each pin of the IC.
So pin one is an adjustable pin with two resistor network to set the output Voltage on the middle/tab pin, the bottom pin (based on your picture) is the input pin.
So the bottom line is what Voltage do you on those 3 pins?

[SDeuce]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

There is continuity from grond to the top pin, from top to bottom as looking at it in the picture

Top: 0.0v
Middle/tab: 1.24v
Bottom: 2.5v

[budm]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

There is continuity from grond to the top pin, from top to bottom as looking at it in the picture

Top: 0.0v
Middle/tab: 1.24v
Bottom: 2.5v

We need to know the resistance reading since continuity can mean 100 Ohms for example. As you can see top pin (pin 1) is connected to GND through R41. R39, R41 are used for setting the Output Voltage on middle pin (pin 2).
Right now input Voltage is too low.
You better report the Voltage readings of all the Voltage regulator at this point. The input of U8 is fed from the output of other regulator.

[SDeuce]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

I will check all the others... Not infinity, but .000

[budm]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

0.000 Ohms? You need to check your soldering work at this point.

[SDeuce]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

I got the Same reading prior to changing the regulator.. Is this a indicator of a shorted resistor for fixing the voltage on that regulator?

Looking at the regulator straight on, tab towards top, theses are my readings:

U2.
2.07
3.33
5.06

U4
2.07
3.33
5.13

U5
1.35
2.59
5.04

U7
2.06
3.31
5.13

U8
0.0
1.24
2.49

U9
1.25
2.49
5.06

I checked voltage on the resistors at U8, r41 0.0v
r39 1.24V Would that resistor drang down the voltage, or cause 0.0 volts on that one pin at u8?

[budm]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

What are the resistance or R39, R41?
Check the resistance between the middle pin of U9 (the one that shows 2.49V) and the bottom pin of U8 (the one that shows 2.49V).
What is the P/N of U9.
BTW, I still did not see the reply regarding to the two fuses on the main board to know if both of them are good or not.
http://www.shopjimmy.com/vizio-3637-...7lhdtv30a.htm#
Vizio 3637-0312-0150 Main Board for VW37LHDTV30A
Pictures provided by shopjimmy.

[SDeuce]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

R41 has .000 resistance R39 has .059 both fuses are fine.. Shopjimmy is out of stock in this board..

[budm]

Re: Vizio vw37L (3637-0312-0150 main board) main board repair

R41 has .000 resistance R39 has .059 both fuses are fine.. Shopjimmy is out of stock in this board..

That made no sense because R41 is connected between pin 1 (ADJ) and GND, R39 is connected between pin 1 and pin 2 (middle pin), so basically output pin 2 is Grounded through R39, R41 which have total resistance 0.059 Ohms, so no way you can have any DCV at the middle pin at all, must be error in measurement.
What scale is the Ohm meter set to? Ohm, K Ohm, M Ohm?