Vizio TV E470VL SMPS Flucuation Output Voltage

[R_J]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

That is just paint marking where the ic is located

[dholley]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

thank you!

[dholley]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

I replaced the IC. No output voltage. Her are the voltages of the IC
1. drain 167
2. Ground 0
3. Vcc 0
4. FB 0.59
5. Sync
6. Vstr 77.2

Any suggestions?

[dskall]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

I didn't see but assume R_J had you check the diode and capacitor connected to pin 4.

[dholley]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

Are you referring to ZD103? If yes, then with power off and in diode test mode it is 1.72 one way and .602 the other

For the capacitor are you referring to c109? If yes, can tell me the best method to test it?

[dholley]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

Any suggestions why no output voltage and no voltage at Vcc.

Q709 Mosfet (pictured attached circled in red) has very low voltage; around 2 to 3 volts and is unstable

[dskall]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

You said you damaged traces. Did you measure on the trace and pin to confirm you have continuity between pin and trace?
I would pull ZD103 a C109 off the board and check them. I would also then check to see if there is any voltage on vcc with them disconnected. Start up voltage is supplied to pin 4 from pin 6.

[nomoresonys]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

You said you damaged traces. Did you measure on the trace and pin to confirm you have continuity between pin and trace?
I would pull ZD103 a C109 off the board and check them. I would also then check to see if there is any voltage on vcc with them disconnected. Start up voltage is supplied to pin 4 from pin 6.

I agree Dskall, I've been suspect of that zener since post 64 at least.

[dholley]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

I have checked the traces and all 6 ic pins and they are good.
I checked ZD103 with another Voltmeter, it shows 0.579v one way and OL the other. My guess is this voltmeter uses less volts for testing compared to the other VM that showed voltage each way. ZD103 and C109 share the same traces for each of side of their leads which might account for why there is voltage each way on ZD103 with the VM that has a higher voltage. I'm not real good in installing or removing SMD so I would prefer to wait on doing that until all other troubleshooting options are exhausted.
You mentioned that start up voltage is supplied to pin 4 from pin 6, can you help me better understand how it works; Is Pin 4 Feed back and Pin 6 Voltage Start up? Pin 6 has 77.2 volts when the power supply is plugged in. This has been about 2 and 1/2 month project and it gets discouraging at times. I appreciate your help.

[Diah]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

hold on... yours OP Photo what are this jumper you did ??? for what?? if its for simulated power on then its wrong.

[nomoresonys]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

I have checked the traces and all 6 ic pins and they are good.
I checked ZD103 with another Voltmeter, it shows 0.579v one way and OL the other. My guess is this voltmeter uses less volts for testing compared to the other VM that showed voltage each way. ZD103 and C109 share the same traces for each of side of their leads which might account for why there is voltage each way on ZD103 with the VM that has a higher voltage. I'm not real good in installing or removing SMD so I would prefer to wait on doing that until all other troubleshooting options are exhausted.
You mentioned that start up voltage is supplied to pin 4 from pin 6, can you help me better understand how it works; Is Pin 4 Feed back and Pin 6 Voltage Start up? Pin 6 has 77.2 volts when the power supply is plugged in. This has been about 2 and 1/2 month project and it gets discouraging at times. I appreciate your help.

No worries on that, the other meter read it correctly, I'd say it's fine.

[dholley]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

The jumpers allow me to check the 5 volt output when the board is right side up

[Diah]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

The jumpers allow me to check the 5 volt output when the board is right side up

you have Stanfby pin i think it is stable 3.3v... this pin need to jumper it with power on /off then you will have 5V and 12V.

[dholley]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

I not sure I understand your post. There is no output voltage of any kind

[Diah]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

I not sure I understand your post. There is no output voltage of any kind

how it come.. then how you were testing LOL
you had the PCB out side the TV. so at plug in wall you dont have Standby V at the socket where you did jumber to your messurements ?? black probe refrences to GND on COLD area.? if you dont have standby then yours HOT area dont work.

[dholley]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

There is 167volts at the filter capacitors and 167 at the drain of the ic pin 1

[nomoresonys]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

Strange indeed.

[Diah]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

There is 167volts at the filter capacitors and 167 at the drain of the ic pin 1

nothings strange.. from start he did wrong. yours post #48 i don't know who told you or how you come to this idea... the threat so long and allot of replacement you did .. good luck

[dholley]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

Hi Diah, I’m just starting out in electronics and welcome any insights you can share about electronics

[Diah]

Re: Vizio TV E470VL SMPS Flucuation Output Voltage

1. The 3 main filter caps all have approximately 167 volts steady
2. I have replaced 4 mosfets next to what I think is called the inventor transformer (big black transformer) pictures attached
3. I have replaced Fuse F102 with an equivalent
4. I have check all diodes and caps and they seem to be ok
5. I replaced the 431 chip at U201

Pictures attached for reference

thank you for your help!!

no problem... we go back to yours first post... why you changed f102.. can you show us the original f102? now u used R .. !!!