TV power board fuse question

Thread Starter

Jrod123

Joined Jan 31, 2016
7
I have a Vizio E500l-B1 with a Power board ADTV3613XA6

The problem is I have no power, no lights on in front.

What I've checked
120 V out of the outlet
120V coming into the circuitboard
But when I check the voltage at the fuse I get almost nothing, but if I remove the fuse and check each end of the fuse holder the voltage is 120v

With the power plugged in and on the DC side I have the following
With everything plugged in
Pic 1
5.15v
Empty
12.3v
15.5v should be 24v
Ps_on 2.95v

Pic 2
15 volts on each 1234 pins should be 24v

Not sure where to go from here.
Any help would be appreciated thank you
 

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Thread Starter

Jrod123

Joined Jan 31, 2016
7
The fuse is a T5 A/250 and have tested it and put a new one in as well, i'm guessing the board is bad but would like to know why
 

SLK001

Joined Nov 29, 2011
1,543
You are doing something wrong. If you are removing the fuse and getting 120V on both sides of the holder, then your measurement techniques are in error. Anyway, you are getting output voltages, so the problem isn't the fuse.

Disconnect the PS from the mainboard and put a resistor between +5 V and PS_ON. This should enable the power supply outputs to be tested. Do this and remeasure the voltages.
 

Thread Starter

Jrod123

Joined Jan 31, 2016
7
Yes I understand how mind-boggling it is but how can my technique be wrong? Remove fuse put one lead on each end
AC mode 125v
With fuse in nothing, I checked multiple points on each end, One lead on each end

But back to testing it, by putting a resistor between PS and +5 V do you just mean like a jumper or just take the +5 V wire out of the connector as well as the PS wire out of the connector and then put a resistor in between them and then do the measurements?
Thanks
 

Thread Starter

Jrod123

Joined Jan 31, 2016
7
I put a jumper between 5v and ps_on with the connector off hoping that's what you meant. And had the same ratings +\- .10 while measuring it.
 

SLK001

Joined Nov 29, 2011
1,543
I put a jumper between 5v and ps_on with the connector off hoping that's what you meant. And had the same ratings +\- .10 while measuring it.
I said a resistor. You risk burning out the supply with a jumper. But it has survived this far, so you will probably be okay. So, you are reading the same values with all the cables disconnected but the input 120V? Are any of the TO-220 devices getting hot to the touch? I suspect a bad capacitor on the cold side is loading the 24V supply (but I can't see anything wrong in the pictures).

The diodes read .57 I think
What diodes? If it is a schottky diode, the 0.57 is way too high.
 

Thread Starter

Jrod123

Joined Jan 31, 2016
7
I said a resistor. You risk burning out the supply with a jumper. But it has survived this far, so you will probably be okay. So, you are reading the same values with all the cables disconnected but the input 120V? Are any of the TO-220 devices getting hot to the touch? I suspect a bad capacitor on the cold side is loading the 24V supply (but I can't see anything wrong in the pictures).



What diodes? If it is a schottky diode, the 0.57 is way too high.
Oops my bad!

The only one unplugged was the one in the the first pic, not sure if they are getting hot, ill feel next time, that's only on the the DC side right?
Yes they look schottky diodes
 
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