I have a vizio 420e that is missing 12vdc on the power supply. 5v standbye is present. I purchased a eprom from SJ and installed it on the main board already. When you push the "power on" button, the main board does send the 3.3v to the power supply telling it to turn on. The Vizio light on the bottom changes color from yellow to white, but that's as far as it goes. Main caps have 168v.
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Vizio vo420e no 12v
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Re: Vizio vo420e no 12v
Please provide us the Voltage readings of all the pins of both connectors:https://www.badcaps.net/forum/attach...6&d=1533524257
Please make sure to put down the pin name and follow by the reading when TV is OFF and when the power switch is activated.
We also need the pictures of the whole backside of the TV showing all the board and straight shot of the whole bottom side of the power supply board.
The more details we have the better. Did someone else work on this TV before?Last edited by budm; 08-05-2018, 09:44 PM.Never 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=24809
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Re: Vizio vo420e no 12v
Sorry BudM Lets try this again
Tv off
168v on main caps
dim-0v
inv on-0
vbr_a-0
blank
status-0
blank-0
on/off-0
12v-0
12v-0
12v-0
gnd
gnd
gnd
gnd
gnd
st/5v- 5.19
st/5v-5.19
st/5v-5.19
TV ON
168v on main caps
dim-0
inv on- 3.28
vbr_a-0
blank
status-0
blank-0
on/off- 3.19
12v-0
12v-0
12v-0
gnd
gnd
gnd
gnd
gnd
st/5v- 5.19
st/5v -5.19
st/5v -5.19
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Re: Vizio vo420e no 12v
Vizio 0500-0412-0750 (PLHL-T802A, 3PCGM10001A-R) PS
http://www.shopjimmy.com/vizio-0500-...wer-supply.htm
I will have to trace out the circuit on the bottom side of the board to get the test points to test.
In the mean while check the fuse F601 (white rectangular box) right next to the two main filter caps.Never 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=24809
Comment
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Re: Vizio vo420e no 12v
Originally posted by shadetreetrader11 View PostFuse is okNever 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=24809
Comment
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Re: Vizio vo420e no 12v
I am looking for resistance.Never 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=24809
Comment
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Last edited by budm; 08-06-2018, 11:33 PM.Never 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=24809
Comment
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Never 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=24809
Comment
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Re: Vizio vo420e no 12v
Originally posted by shadetreetrader11 View PostI imagine you want me to trace the 3.3v from the "power on" pin back to some form of an oscillator IC?
It looks like PC102 is the one.Last edited by budm; 08-07-2018, 10:05 AM.Never 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=24809
Comment
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Re: Vizio vo420e no 12v
Can you read U801 PFC controller IC, we may be able to trace the VCC pin of that IC back to the switched Transistor that supplies the switched VCC.
So far it looks like OPTO PC102 is used for turning on Q101 to supply VCC to run the PFC IC.
You need to check VDC at the Collector and Emitter with ref. the hot side circuit GND which will be the negative leg of the main filter cap in the hot side.
Make sure to at least plug the TV into the GFCI outlet.Last edited by budm; 08-07-2018, 10:10 AM.Never 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=24809
Comment
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Re: Vizio vo420e no 12v
Got to looking at Q101 and if you zoom in you can see a burn spot right in the center of it. If you click on the white picture above the image of the green circuit board there are some voltages for you to look at. I didn't know how to resize it. And Opto PC102 looks like it is the one that goes directly to this transistor.
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Re: Vizio vo420e no 12v
It does look bad, it is a NPN Transistor, the Collector get the DC input Voltage from the AUX winding of the standby power supply, the Emitter pin is the output pin that feed the VCC to the PFC IC.
BTW, when look at the transistor with the two legs pointing down, the left pin is the Base which gets the bias current from the Opto to turn it on when PS-ON is present then the output at the Emitter goes to the PFC IC.
At this point we need to verify that there is no low resistance reading between the hot side GND and the Emitter since the output may be seeing the shorted/very low Ohm so it damage the Transistor.Never 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=24809
Comment
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Re: Vizio vo420e no 12v
I believe Q101 is the VCC switch, It should have voltage (18-20 volts?) on the collector (use hot ground to measure).the base should have a zener diode (likely 15 volt) and the emitter supplies the VCC voltage (15 volts) for the pfc ic U801.
PC102 should be the opto that turns on the Q101. If q101 is burnt, the pfc ic U801 may or may not be shortedLast edited by R_J; 08-07-2018, 09:15 PM.
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Re: Vizio vo420e no 12v
Emitter to hot ground is 30 ohms. I think you guys mean u601 instead of u801. U601 is a FAN7530. And the Emitter goes directly to the VCC or pin 8 of the U601 IC. I also measured all the other pins of U601 to hot ground and they were all above 1k ohm.
I should also note that the readings were done with the transistor removed from the circuit.Last edited by shadetreetrader11; 08-07-2018, 10:04 PM.
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