VIZIO VO370M - orange light but does not turn on

[garry7263]

I got this for free and really can't afford to spend much money to fix it so I need to troubleshoot it.

Starting with the power supply board. I get 5 volts on the three pins, and I do get 12 volts out of the 12 v pins when I jump the pson pin to one of the 5v pins. I have pulled and checked the caps, and the diodes on the heat sink near the DC output. What else should I be checking.

Question about the Diode in the d106 position. I think it is not good since it reads OL in both directions. The numbers are T2D 91 (underscore on the 1) written in blue letters. I cant find any information on this diode.

Pics: top then bottom whole
close ups of quarter sections

[retiredcaps]

Re: VIZIO VO370M - orange light but does not turn on

Question about the Diode in the d106 position. I think it is not good since it reads OL in both directions.

Remove D106 from board and retest out of circuit. If it still shows 0L both directions out of circuit using the diode test function on your multimeter, it is likely bad.

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

I have already unsoldered one leg on all the diodes and tested them all. This one showed OL both way and I pulled it out completely and double checked it. I know it bad and needs to be replaced. I have no value for it so I don't know what to replace it with or able to cross reference it. I searched all over the net.

I am starting with the power board to try to get the inverters to click on before moving on to troubleshooting the Main Board.

BTW, What voltage is needed to turn the inverters on at the pin and what voltage should I get, when the solenoids click, on the output?

[retiredcaps]

Re: VIZIO VO370M - orange light but does not turn on

Hmm, on second thought, see this thread

https://www.badcaps.net/forum/showthread.php?t=23233

[retiredcaps]

Re: VIZIO VO370M - orange light but does not turn on

BTW, What voltage is needed to turn the inverters on at the pin and what voltage should I get, when the solenoids click, on the output?

BL_ON (backlight on) usually needs to be > 3V DC in order for the backlights to come on.

[budm]

Re: VIZIO VO370M - orange light but does not turn on

At this point I would find out why the main board is not sending out the PS_ON signal, at the same time more likely that is also not sending out the BL_ON signal and the Dim signal..
That Diode is more likely to be snubber Diode as I explained in that link.
If the main board is getting the 5V to run, then it should be putting out the PS_ON, BL_ON, and Dim signals.

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

I put the diode back. I get 5v and 12v on their respective pins. Jumping the INV_ON pin, I get a LED that lights up on the back side, then fades out. No clicking of the solenoids though. Sampling most of the points I get 69.4 volts on most of it, on the hot side.

Just so you know, my knowledge is mostly limited to some tube amps and guitars, with some success with a few other electronics so I am trying to learn. My father was an electrical technician for GE originally, then Gates and finally Eastman Kodak.

Will post some pics of the main board.

[budm]

Re: VIZIO VO370M - orange light but does not turn on

So are you getting the PS_ON, BL_ON (inv_on) signals at the power supply board? When you measure the voltages on the hot side, you do not use chassis ground as the ref point (that is why you are getting 69V reading), you use the negative leg of the large filter as the ground ref point for the hot side of the circuits.

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

here are pics of the main board

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

some pics of the back

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

when I bridge the INV_ON I do not hear the solenoids clicking so that leads me to believe something in the power supply is not working.

[budm]

Re: VIZIO VO370M - orange light but does not turn on

Well, we are not getting the answer, do you get > 3v at the PS_ON pin and the BL_ON (INV_ON) pin? They are generated by the main board when the TV is turn on, if not, then you will need to troubleshoot the maim board starting by checking all the voltage regulators.
Please read the how to at the bottom of my signature and report the reading as shown by retiredcap.

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

ok, well this is weird...

I have both boards out on my table connected with the jumper. Plugged in the power board tested the DC volts out, all with steady 5VDC.

Checked the fuse on the main board and reads 5.19 volts

initially I checked the following voltage regulators

U2
8DZ
1117L
1 - 0.65v
2 - 1.60v
3 - 4.96v (fluctuating)


U8
8DZ
1117L
1 - 0.00v
2 - 1.25v
3 - 3.31v (fluctuating)


U5
8DZ
1117L
1 - 1.38v
2 - 2.64v
3 - 4.92v (fluctuating)


U4
8DZ
1117L
1 - 2.06v
2 - 3.31v
3 - 5.02v (fluctuating)


U7
1084
0851JL
1 - 2.04v
2 - 3.29v
3 - 4.94v (fluctuating)


U9
8DZ
1117L
1 - 1.26v
2 - 2.52v
3 - 4.92v (fluctuating)

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

After double checking the values two times I noticed that the third time the fluctuating input current read steady with the following values


U2
8DZ
1117L
1 - 2.06v
2 - 3.32v
3 - 5.08v


U8
8DZ
1117L
1 - 0.00v
2 - 1.25v
3 - 3.31v


U5
8DZ
1117L
1 - 1.38v
2 - 2.64v
3 - 5.10v


U4
8DZ
1117L
1 - 2.06v
2 - 3.30v
3 - 5.14v


U7
1084
0851JL
1 - 2.05v
2 - 3.31v
3 - 5.11v


U9
8DZ
1117L
1 - 1.26v
2 - 2.52v
3 - 5.11v

After which I tried pressing the power button and I got 12VDC on the second fuse. getting 12 VDC on the power board. Still the LED on the back of the power board glows but then fades and then the 12VDC on the main board fluctuates sometimes a little. If I push the power button again the VDC on the fuse drops as i should.

Something must be making the power fluctuate when it is first plugged in, but works when it is warmed up.

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

The black capacitor in pic 6 of the main board (bottom left corner by the U2 IC) gets really warm. Not sure if that is normal.

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

So I plugged the boards back into the unit and powered it up to check. The orange light stayed on steady. I pushed the power button and the light changed and went to white. I lifted up the panel and checked the screen and the screen was blue and said no signal. I would say the TV is now working and will test it with signal when I put it back together. Maybe pulling out a bunch of capacitors and resoldering them was all it needed. Still don't like the inconsistent readings.

I would say it is working but still not fixed. More than likely, there is still something wrong with the main board. I am thinking maybe a bad capacitor (or on the verge of failing) I will make a ESR meter to test the caps on the main board.

Will test shortly and report back

[vinceroger69]

Re: VIZIO VO370M - orange light but does not turn on

hopefully it was just a cold joint on the soldering you never know just keep trying it over a few days turning it on and off etc but as you say maybe a bad cap with esr issues and heating it up to test replace has somehow got it to a workable condition?

[garry7263]

Re: VIZIO VO370M - orange light but does not turn on

YAY!! TV working on cable. tried it on my brother's computer but it said "not support" I am assuming that it is a driver issue. So for now I will see how long it lasts. Not bad for a free TV, just testing a few components and resoldering a few connections. Thank you for all the help BudM and Retiredcaps.

Time to go find another TV to experiment on till this one goes on the fritz.

[MisterD]

Re: VIZIO VO370M - orange light but does not turn on

The circuit board mounting screws also make ground connections from the chassis to the boards, it's possible that some of them weren't snugged down tight causing the initial problem.