Re: Vizio TV E470VL SMPS Flucuation Output Voltage
I wanted to thank everyone for their help in trying to fix this power supply. I was not available to fix it an ended up buying replacement at BuyQual.com at a reasonable price.
thank you and God's Blessings,
Danny
dholley
Mr. Blinky
Last Activity: 10-02-2023, 01:32 PM
Joined: 01-04-2022
Location: Montgomery, Texas
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
There is only 1 volt at Q707 at the drain. Picture attached. For orientation it is right next to big filter cap, cap farthest away from input power. Any suggestions?...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
How do test Q101 and 131 in circuit with a multimeter?...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
Any ideas why there is changing voltages on these mosfets? The mosfets just above them are steady and stable at 167 volts...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
No standby voltage, no output voltage of any kind...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
167 volts on the filter caps...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
Yes...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
Negative side of big capLeave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
In the attached picture these two MOSFETS, voltages seems weird, is it normal that when I measure in DC VOLTS at the drain, voltage starts out as high as 27 volts and lowers down to 9 volts?...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
It is a head scratcher! I replaced the zener diode and the cap. There is approximately 2.2 volts at Vcc which is better than zero I guess. But still no output voltage. With the power off and multimeter in diode mode Vcc to ground shows about 1.47 volts, before changing the zener I think it was approximately.02 volts.
I sprayed the board front and back with freeze spray with power on but did not find any obvious shorts.
Any suggestions?Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
When installing the zener diode does the dot / bar go to the pointed arrow side ?
I lost the capacitor, I think it is 66 pf, how critical is it match the original cap?Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
Ok...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
Correct...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
The cap charges up very quickly in ohm mode, so there is not really a measurement for before it goes to OL...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
As of yet I don't see a diode on Vcc Pin 3, I don't see a 10uf cap, but there is a 47uf. I have tested that cap I think it is approximately 43uf...Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
The ZD104 has 18 ZD written, so is that an 18 volt zener diode? I found cap c107 buried in some alloy, it is about the 1/4 the size of a pencil tip. If I did it correctly is measures about 66 pf, does that sound right? It was not short.Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
thank you!Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
our messages occurred at the same time so I have you answer about the zener. Can you tell me if the cap is polarized?Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
At the the moment I think the Cap is covered with alloy, because I don't see the part anywhere else!!! and with that testing is not possible. Any idea about a replacement part for the zener and cap? Are those types of capacitors polarized?Leave a comment:
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Re: Vizio TV E470VL SMPS Flucuation Output Voltage
I removed ZD104 and C107. ZD104 shows about 0.2 in diode mode each way. I’m assuming that would be a bad zener diode, would someone please confirm. It was not my intention to remove C107 at the same time as ZD104 but I used alloy and the zener and cap are so small and close to each other i inadvertently knocked it off. I think the cap is covered in alloy so I’m trying figure out how to clean it. Some good news I think, with the zener and cap removed there is some output voltage all be it low and fluctuating. Can some...Leave a comment:
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