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Old 01-15-2020, 04:09 PM   #1
henryvrensburg
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Default Vizio D65u-D2 not switching on

Good day guys

I got this Vizio D65u-D2. I've read all the other threads about this specific model, but all got to do with Backlights.When plugged in, there is no Standby Light, also set doesn't switch on or no sound coming from set when switched on(regulators etc)

With AC connected - not switched on - and Connectors to Mainboard and LED Driver board I found the following readings on connector CN101

1. 5.103V
2. 5.103V
3. 0.043V(fluctuating)
4-16. No readings, although some may differ from 0.0 to 0.25/0.35

With AC Connected - connectors to Mainboard and LED Driver board connected - power button pressed, the following readings on CN101

1. Fluctuates. Range 0.809V to 5.070V
2. Same as 1
3. Fluctuates from 2.4 to 3.09V. Even less than 2V at stages
4-16 No Readings

I am a complete novice, and would appreciate any help. Thank you for reading this.
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Old 01-15-2020, 04:47 PM   #2
R_J
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Default Re: Vizio D65u-D2 not switching on

The fault appears to be with the standby voltage CN101, pins1&2, this voltage needs to stay at +5 volts. It is either something on the main board that is killing this voltage OR the power supply can't supply enough current for the standby voltage to remain at 5V
Check C511, C517 and also the output cap C?? next to D201
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Old 01-15-2020, 05:31 PM   #3
henryvrensburg
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Default Re: Vizio D65u-D2 not switching on

Hi R_J, I checked on those three caps. For good measure I replaced all three with new caps. Result still the same. Still fluctuating voltages on 1,2 and 3
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Old 01-15-2020, 05:55 PM   #4
R_J
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Default Re: Vizio D65u-D2 not switching on

If you have a 10Ω, 3~5 watt resistor you can try loading down the 5v standby on the power supply (disconnect CN101 from the main) That would draw about 500ma from the standby and if the voltage still drops, the power supply is at fault.
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Old 01-15-2020, 05:59 PM   #5
henryvrensburg
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Default Re: Vizio D65u-D2 not switching on

I can get a 10 ohm resistor, but can you explain how to "load" the 5V or what should I do with the resistor.
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Old 01-15-2020, 06:12 PM   #6
R_J
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Default Re: Vizio D65u-D2 not switching on

You just connect the resistor between +5v standby and ground, to see if the standby voltage stays up. Also check if the +5v is dropping at D201 Cathode?

1. Fluctuates. Range 0.809V to 5.070V
2. Same as 1
The standby voltage can not drop like you measured it. When the voltage drops to .8 volts the main board no long functions. This voltage must stay at 5v

Last edited by R_J; 01-15-2020 at 06:16 PM..
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Old 01-17-2020, 03:38 PM   #7
henryvrensburg
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Default Re: Vizio D65u-D2 not switching on

Hi R_J

I did as you suggested. I soldered in a 10ohm resistor in between the 5VSB and the Ground on CN101. I took out all other connectors on the PSU. The voltage fluctuations on 5VSB still occurs. Am I looking at another PSU, or can you help me with some component repair.
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Old 01-17-2020, 05:32 PM   #8
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Default Re: Vizio D65u-D2 not switching on

Check all diodes if any read off lift a leg out of circuit and check again, check for bad/cold solder joints on bottom side of board, look closely at the solder joints of components on heatsinks and on transformers, sometimes they look good but are bad or loose.
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Old 01-17-2020, 06:40 PM   #9
henryvrensburg
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Default Re: Vizio D65u-D2 not switching on

Hi nomoresonys

Thank you for your reply, I checked all diodes, also re-soldered all components with heatsinks, PSU still not working. I can get a PSU for about $40, so maybe that is the way I should go.

Thank you
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Old 01-18-2020, 04:24 AM   #10
nomoresonys
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Default Re: Vizio D65u-D2 not switching on

Maybe try heating the powerboard with a hairdryer, heat all the caps n optos n such, then see if it starts up or anything changes.
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Old 01-18-2020, 10:27 AM   #11
R_J
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Default Re: Vizio D65u-D2 not switching on

If the standby is fluctuating with just a 10Ω load, check U501's vcc and see if it is steady, This voltage needs to be around 16 volts, if it drops below 10 volts the ic restarts. Check the feedback voltage on pin 4, (post the voltage)
check the winding resistance of T501 (pins 1&2), R525,D505,R502?
Then check R527, and ZD506 (lift one end of ZD506 to check)
The problem could also be on the secondary side, Try swapping pc502 with pc501 (if they are the same)

Last edited by R_J; 01-18-2020 at 10:43 AM..
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Old 01-27-2020, 08:25 PM   #12
henryvrensburg
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Default Re: Vizio D65u-D2 not switching on

Hi guys

I tried some component repair on the Power Supply, but was unsuccessful. I bought a new Power Supply, and now my TV is working.

Thank you for pointing me in the right direction. Much appreciated
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Old 01-28-2020, 06:04 AM   #13
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Default Re: Vizio D65u-D2 not switching on

Glad to hear it, thanks for feedback.
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