Im working on a VIZIO model SV420M, according to my buddy it just quit working and never had any warning signs before it failed. I opened it up and when plugged in it has 5.1v standby voltage, but when the power button is pressed the power supply doesn't fire up. Can anyone point out some possible problem areas for me to check? When i force the power supply on all voltages are present, so i think this may be a main board issue. Thanks for any and all help.
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Re: VIZIO SV420M stuck in standby
Heres the board in question.Attached Files -
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Re: VIZIO SV420M stuck in standby
Check if the main board returns PSon on the PSU. No PSon = main board problem.
These sets are known for bad voltage regulators on the main board. So check those if they are putting proper voltages out.Last edited by CapLeaker; 07-31-2016, 11:39 AM.Comment
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Re: VIZIO SV420M stuck in standby
It doesno ruturn 5v to power supply, is there a specific component or set of components that i should look at?Comment
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Re: VIZIO SV420M stuck in standby
I can't see what like U6 or U3 is. Anyhow, get the numbers off them, get the spec sheet so you can see the pin out and post the stuff here which regulator, the number printed on the regulator and the 3 pin names you measured (in, out, adj).Last edited by CapLeaker; 07-31-2016, 12:02 PM.Comment
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Re: VIZIO SV420M stuck in standby
Disconnect the main board from the power supply and power up and see if the backlights come on and what other voltages you have on the connector.
If you only have 5V standby then connect that to P_On(Power ON, On_OFF) using a 1K resistor, switch back on and check the voltages again on the connector.
As Capleaker said you have a few 117 devices on the board that could be checked out and also a couple of white smd fuses you could check for continuity.Last edited by dick_barton; 08-01-2016, 02:42 AM.Willing to help but I'm no expert.Comment
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Re: VIZIO SV420M stuck in standby
I have removed the main from the circuit, jumped 5v standby to inverter on and ps on simultaneously and the backlight fired, and i recied 12v at the premarked 12v rail. I did not test the backlights voltage as it is functioning, taking test and dicks advice im testing the components around u6 and u3, there are 2 different types looking up the first one for testing purposes i found the datasheet and was looking for reference voltages and found this page. Can i assume that is the voltages i should see at the pins for these 2 components?Attached FilesComment
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Re: VIZIO SV420M stuck in standby
The white smd fuses are good.Comment
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Re: VIZIO SV420M stuck in standby
I cannot identify the components in u2 u4 u6 and u7 they are all the same, and appear to have 1117 966 D11 printed on themComment
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Re: VIZIO SV420M stuck in standby
Those are 1117 voltage regulators.Comment
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Re: VIZIO SV420M stuck in standby
Voltage Regulator (LDO) testing:
https://www.badcaps.net/forum/showth...999#post300999Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: VIZIO SV420M stuck in standby
HComment
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Re: VIZIO SV420M stuck in standby
#1
Gnd/adj 4.3 mv
Out 1.42v
In 3.29v
#2
Gnd/adj 2.07v
Out 3.32v
In 5.012v
#3
Gnd/adj 6.91v
Out 8.17
In 12.20v
#4
Gnd/adj 2.05v
Out 3.305
In 5.86vAttached FilesComment
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Re: VIZIO SV420M stuck in standby
#1
Gnd -1 mv
Out 3.29v
In 4.99v
#2
Gnd 2.048v
Out 3.29v
In -4.2vAttached FilesComment
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Re: VIZIO SV420M stuck in standby
The screen was stable when i jumped the power supply, it appears to be on, without an image.Comment
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Re: VIZIO SV420M stuck in standby
I did also notice that the bga chip on this set gets smoldering hot even though the set can't power on. Is this a sign that there might be a bga issue?Comment
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Re: VIZIO SV420M stuck in standby
My friend decided to buy the board istead of repairing, but i'm asking for future reference, i always assumed that such a chip should be inactive untill the set is booted. Its the chip under the cooling fin in the pic.Attached FilesComment
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Re: VIZIO SV420M stuck in standby
Quite possible that the bga chip has gone north. If it's that hot it may have lost some of it's connections to the main board which is one of the problems that is discussed quite often on the forum.Willing to help but I'm no expert.Comment
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Hi. I got a Vizio with no power or standby, and won't turn on with remote or button. I checked the voltages on the connector and all read 0.00V or nearly 0(0.050 ON/OFF pin). None of the pins are labeled STB for standby although I do see some 5V pins. Other than the obvious standby led, which isn't coming on, is there a way to check for standby voltage on this PS. I'm trying to see if my problem is the PS or mainboard. Some Vizios I have fixed with no standby led me to think it was the PS but it turned out being the mainboard. Any experience with this set would be greatly appreciated. -
Hi guys, I’m back here my friend give me her tv, that doesn’t turn on and no standby red led. When u plug in the cord the red led of one two second is on, then turn off. If you push the power button or the remote the red led blinks but nothing happen. I give u some photo with voltage, don’t look the fuse….because I blow it for mistake nd I dint have the right replace so I just put it for test the tv. The standby voltage should be 11,88 volt on the diode, but I have 13 volts. I put in the photo the different volts I test and there are someone negative…I don’t know if it s normal. On... -
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Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
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Assuming... -
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I suppose the real question is whether the existing pinouts from ether a 17IPS71 psu are cross compatible with a 17IPS12 psu? If they are then the exchange of the main boards should have no issues providing the screen is compatible with both main boards. Obviously you can change the screen configurations easily enough (providing you have the correct files) for the main board. Why may you ask would I do this? Well a lot of the smart features are no longer working on a Hitachi 48HBT62U main board I wish to give it a new lease of life!
Obviously the same LVDS connector for the screen connection...
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