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Old 09-14-2018, 06:44 AM   #1
Rainy
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Default Standard Vizio Power Supply DPS-167DP

Hello. I just want some thoughts on a power supply I'm repairing.
I searched the forum and didn't find much on this power supply.



The IC failed. It looked like it exploded kind of. I got 5 off eBay and replaced it (with that terrible rosin solder..)

The IC gets like 9 volts on every pin except for the two separate drain pins that fluctuate between like 10 and 12 volts every half second or so.

The secondary side has no standby voltage (5vSB) and the diode is short and I haven't replaced it yet. Any thoughts on what else I should test? I didn't notice any shorts on any mosfets.

For reference for anyone with future repairs: https://www.datasheets360.com/pdf/732173695424627367
The IC is: LD7913JGM6
The TV is: M492i-B2
Manufacturer: Vizio

(also search does not work on this site? odd)

Last edited by Rainy; 09-14-2018 at 06:52 AM..
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Old 09-14-2018, 09:17 AM   #2
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Default Re: Standard Vizio Power Supply DPS-167DP

Lets start with what did you use for GND ref for your meter when you get those Voltage readings?
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Old 09-14-2018, 09:46 AM   #3
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Default Re: Standard Vizio Power Supply DPS-167DP

Quote:
Originally Posted by budm View Post
Lets start with what did you use for GND ref for your meter when you get those Voltage readings?
I used the top-right screw ground. Bottom-right in the photo.
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Old 09-14-2018, 09:48 AM   #4
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Default Re: Standard Vizio Power Supply DPS-167DP

OK, you use wrong GND ref. that is why your readings are all wrong, you are working on the hot side of the circuit so you have to use the negative leg of the main filter cap for the circuit GND ref for the hot side.
Did you also check the resistors R907A, 907B connected to the S pin of the IC and the hot side circuit GND to make sure they are still OK?
You also need to check the fusible resistor R915 to make sure it is also OK.

Last edited by budm; 09-14-2018 at 09:59 AM..
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Old 09-14-2018, 09:55 AM   #5
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Default Re: Standard Vizio Power Supply DPS-167DP

Quote:
Originally Posted by budm View Post
OK, you use wrong GND ref. that is why your readings are all wrong, you are working on the hot side of the circuit so you have to use the negative leg of the main filter cap for the circuit GND ref for the hot side.
Did you also check the resistor connected to the S pin of the IC and the hot side circuit GND to make sure it is still OK?
That just blew my mind.

Sorry, I really don't know what the main filter cap looks like.


I'm not sure what pin is the S pin. And, I'm not sure what resistor
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Old 09-14-2018, 10:03 AM   #6
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Default Re: Standard Vizio Power Supply DPS-167DP

See my updated post #4.
Main filter cap is C800A.
Look at the spec sheet of the IC, it shows which pin is the S pin.
You are working in the hot deadly side of the circuit so you need to at least plug the TV into the GFCI (Ground Fault Circuit Interrupter) and do not touch anything on the board with yours hands or body.
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Old 09-14-2018, 10:28 AM   #7
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Default Re: Standard Vizio Power Supply DPS-167DP

Quote:
Originally Posted by budm View Post
See my updated post #4.
Main filter cap is C800A.
Look at the spec sheet of the IC, it shows which pin is the S pin.
You are working in the hot deadly side of the circuit so you need to at least plug the TV into the GFCI (Ground Fault Circuit Interrupter) and do not touch anything on the board with yours hands or body.
Funny, because that breaker doesn't trip in our place at all.
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Old 09-14-2018, 12:06 PM   #8
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Default Re: Standard Vizio Power Supply DPS-167DP

I am not talking the circuit breaker, I am talking about using GFCI outltet such as one used in the bathroom.
You know what GFCI outlet is, right? It is for your own safety unless you do not care.
https://home.howstuffworks.com/question117.htm

Last edited by budm; 09-14-2018 at 12:07 PM..
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Old 09-16-2018, 01:04 PM   #9
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Default Re: Standard Vizio Power Supply DPS-167DP

Quote:
Originally Posted by budm View Post
I am not talking the circuit breaker, I am talking about using GFCI outltet such as one used in the bathroom.
You know what GFCI outlet is, right? It is for your own safety unless you do not care.
https://home.howstuffworks.com/question117.htm
I went and measured that same chip again. I get ~50v now on all of the pins except the drain to the mains filter cap (I guess those are on the front visible side)

I also get ~50v measuring to the 5VSB from the mains filter caps.

This is a new voltmeter, it read 5v last time I checked.

Can anyone else chime in with some advice?

I know that diode is bad, but it has no power to it at all.

Last edited by Rainy; 09-16-2018 at 01:05 PM..
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Old 09-16-2018, 01:47 PM   #10
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Default Re: Standard Vizio Power Supply DPS-167DP

there is a reason for that white checkerboard marking on the board, it tells you what components are on the HOT side and which are on the COLD side. ALL voltages on the HOT side are measured with reference to the HOT GROUND (Main Filter or bridge rectifier (-)).
All voltages on the COLD side are measured to Chassis ground (like 5 volt standby)

What do you mean by THAT DIODE???? they have board locations.

Last edited by R_J; 09-16-2018 at 01:49 PM..
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Old 09-16-2018, 03:07 PM   #11
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Default Re: Standard Vizio Power Supply DPS-167DP

Update: I just soldered on a new diode from a VCR that was "40" instead of "30" and works great.

Thanks for pointing me in the right direction. I realized the TV was tripping after I measured power from the mains cap on both sides in voltage mode and hitting the power button. The Meter would go out of range about 10 times, then TV would be in standby mode.
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Old 09-16-2018, 03:09 PM   #12
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Default Re: Standard Vizio Power Supply DPS-167DP

Quote:
Originally Posted by R_J View Post
there is a reason for that white checkerboard marking on the board, it tells you what components are on the HOT side and which are on the COLD side. ALL voltages on the HOT side are measured with reference to the HOT GROUND (Main Filter or bridge rectifier (-)).
All voltages on the COLD side are measured to Chassis ground (like 5 volt standby)

What do you mean by THAT DIODE???? they have board locations.
The one marked in red on the photo. Sorry man, it was kind of hard to see. it's working anyway

I recorded the repair on camera of the diode addition:
https://youtu.be/5MKF0J0qMVM

Last edited by Rainy; 09-16-2018 at 03:17 PM.. Reason: https://youtu.be/5MKF0J0qMVM
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Old 06-01-2019, 10:12 PM   #13
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Default Re: Standard Vizio Power Supply DPS-167DP

Hi
I am currently working on a Vizio E480i-b2 power supply. The T.V. would not turn on at all. I have no 5 or 12 volts on the secondary side. I do have the voltage on the primary side. I do get 160 volts at R915 fuseable resistor on one side and only 1.5 volts on the other side. Have no power at T601 primary side. Also only 1.5 volts on T901 on one leg and no other voltage on the other three legs. I am thinking the IC 901 may be bad but I need to replace 1 bad diode before I can go any further. Resoldered all solder joints with any cracks. Checked all capacitors, resistors, ferret beads. diodes, transformers. Only found 2 bad diodes. zd909 which is a nz4v7d replaced with a nz6v8b didn't make a difference. Found diode D950B to be shorted. I need to replace this diode.My question is that is there another diode I can use in place of this one?. I can't find any in all of the boards I have and would like to find a replacement diode.
Thank You for your help
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Old 06-01-2019, 11:01 PM   #14
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Default Re: Standard Vizio Power Supply DPS-167DP

That 4.7 Ohms fusible have gone bad due to shorted out SMPS IC901. P/N of IC901?
That D950B is just rectifier for the 5VSTBY of that section, it is just schottky diode, 100V 3A rating should be fine, so if have another SMPS 5V power supply board with about the same rating then you should be fine.
"Only found 2 bad diodes. zd909 which is a nz4v7d replaced with a nz6v8b " I would out in the same value, they put 4.7V Zener for reason. Is it tested bad off the board? It is connected in parallel wirh R907A/B so it will show conduction in both directions when tested in circuit. See post #4.

https://www.shopjimmy.com/vizio-056-...ed-driver.htm#

Last edited by budm; 06-01-2019 at 11:09 PM..
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Old 06-03-2019, 10:06 AM   #15
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Default Re: Standard Vizio Power Supply DPS-167DP

I'll work on replacing the fusible resistor, IC901, D950b. Diode zd909 was checked out of circuit. I wasn't sure how to read diode value now that I know it will be easier to read them. if a part doesn't give the correct reading I always check it out of circuit. Thank you for the information I will get back to you when the parts are replaced.
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