Vizio VO42L question

[tibimakai]

Re: Vizio VO42L question

What kind of voltages should I expect at the FET transistors or transformer inputs?
On the secondary transformer inputs, all the inputs are 5.8V, and on the master all the inputs are 0.228V.

[budm]

Re: Vizio VO42L question

There will be 24V at the Drain of two MOSFET's top half of the bridge setup, the drive is a full bridge setup, since all the MOSFET's are off when they are not driven by the IC, the Source/Drain center connection will be 0 volt, the transfomer has DC blocking caps which means you will not see any DC voltage reading on the primary winding, see the SCH I provided earlier.

[tibimakai]

Re: Vizio VO42L question

I'm not that good to be able to diagnose this any further.
I have re-checked both boards, I have notices some solder ball under the slave chip and by trying to remove it from behind the chip's pins I have noticed that one of the pins wasn't soldered properly.
So went through both chips again and after re-soldering each pin, I have got a change on the master board.
I have almost the same voltages as the slave FETs, but still a no go.
MQ1
G- 5.6V
D- 25.05V
S- 5.6V

MQ4
G- 5.5V
D- 25.05V
S- 5.5V

MQ2
G- 0V
D- 5.6V
S- 0V

MQ5
G- 0V
D- 5.5V
S- 0V

[tibimakai]

Re: Vizio VO42L question

Any other input would be appreciated.

[tibimakai]

Re: Vizio VO42L question

There is only one fuse on these boards or there is another one?
I see in repair kits they sell a 0.1ohm fusible resistor also with the IC and FET transistors.
I also see some new replacement boards from China, anybody has any experience with these? Both for $36!!
http://www.ebay.com/itm/Brand-New-Re...item4d03e71e27
or from an US seller for $38
http://www.ebay.com/itm/New-Inverter...item27ca031509

[budm]

Re: Vizio VO42L question

I saw those kit with the 0.1 Ohm resistors in the kit, it does not say where they used at, i am sure they want you to buy the kit to find out where they go.
$38 for both is cheap!

[tibimakai]

Re: Vizio VO42L question

Cheap and hopefully the problem it's gone. I will look one more time at this TV and if I can't see anything wrong then I will buy these boards.

[tibimakai]

Re: Vizio VO42L question

OK, I have got those new style boards in and the TV it's alive!!!
The only issue I have is that I can't install the metal shield on them.

[budm]

Re: Vizio VO42L question

Glad to hear that they fixed the problem. I left my metal shields off, it will run cooler, and since they are inside the TV, the customer cannot get to them unless they open it up.