Identify The Chip??? Vizio E480i-B2

[nomoresonys]

Re: Identify The Chip??? Vizio E480i-B2

While you have them off the board check them again.

[R_J]

Re: Identify The Chip??? Vizio E480i-B2

on the same board there are two high voltage diodes D200 and D120, one is reading a short and other is reading like it's charging, probably coming from a cap.. can anyone identify these, please.???

Remove them and look at the numbers, They are dual diodes, I doubt they are bad.

[stu007]

Re: Identify The Chip??? Vizio E480i-B2

Ld7913 , R915 is likely open as well

on the same board there are two high voltage diodes D200 and D120, one is reading a short and other is reading like it's charging, probably coming from a cap.. can anyone identify these, please.???

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

Yea, this has become a little over my pay grade.. Knuckle dragging ground pounder type tech..

It didn't help that the thread was conflated with another board.. That's on me..

Thanx for all the help.. I can pick up a replacement for around $12 and that seems to be the path of least resistance right now..

Thanx again...

[budm]

Re: Identify The Chip??? Vizio E480i-B2

OK I disconnected the Power PCB completely..

The ohm reading on that resistor stayed the same..

The voltage on the chip flashed between 0.L and .000 constantly..

O.L (Over range (too high) for the meter to display) and 0V seems like the circuit is in startup/shutdown loop.
And you look at the DC Output of this standby power supply, do you see any DC output jumping up and down?
You also need to check the Voltage on the Brown out protection pin of the IC also.

[R_J]

Re: Identify The Chip??? Vizio E480i-B2

I can only go by the picture in post #21 where you get 10-15 volts on pin 5 VCC, that voltage is likely coming from the internal startup cell of the ic, What you should check are the two resistors R605 & R606, they are in parallel so whatever the value is on one, the resistance across both should be half the value. Also check R607 & D612
I would also Replace C602
Once the ic pulses the transformer primary, a run voltage should be supplied by the secondary winding connected to D601 which would charge C602, maybe to around 20 volts. this voltage will be supplied to the vcc pin via R607 &D612.

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

I am knocking off for the day. Pick it up first thing in the AM..

Thanx to all for the assist...

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

OK I disconnected the Power PCB completely..

The ohm reading on that resistor stayed the same..

The voltage on the chip flashed between 0.L and .000 constantly..

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

That is fine, I expect that Source resistor will blow open circuit when that IC blew up.
Did you verify that the rectifier on the cold side of that standby power supply are OK?
There are two startup/running lytics caps in that section that you should also verify.
You are running the power supply board by itself without having it connected to other board, correct?

Nope.. Hooked up to the LED strips and the main board...

I can pull those connections, but will the reading be correct not being "turned on" so to speak??

[budm]

Re: Identify The Chip??? Vizio E480i-B2

That is fine, I expect that Source resistor will blow open circuit when that IC blew up.
Did you verify that the rectifier on the cold side of that standby power supply are OK?
There are two startup/running lytics caps in that section that you should also verify.
You are running the power supply board by itself without having it connected to other board, correct?

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

May be you should lift one leg off the board and check it again.

Starts at .2 ohm then up and holds steady at 1.2-1.3 ohm

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

May be you should lift one leg off the board and check it again.
BTW, did the IC blow its top just like the one in post 1?

Yes it did.. total Mt Vesuvius...

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

As in the pic, the voltage fluctuates between 10 and 15 volts..

[budm]

Re: Identify The Chip??? Vizio E480i-B2

May be you should lift one leg off the board and check it again.
BTW, did the IC blow its top just like the one in post 1?

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

3) If it is the board is post 10, then check the Source resistor R601 to make sure it still show <1 Ohm.

Starts at .4 ohm then goes up in a sec or two and holds steady at 1.4 ohm

[budm]

Re: Identify The Chip??? Vizio E480i-B2

1) You are working in the HOT Deadly side of the circuit so the Black probe of your meter should be connected to the negative leg of the main filter cap C120.
2) If you measure the DC Voltage between the two legs of the main cap, do you get about 160V DC?

[vinceroger69]

Re: Identify The Chip??? Vizio E480i-B2

im still learning but as this ic is on the hot side of the psu i would use the negative side of the main filter capacitor as a ground im sure budm will confirm for me

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

1) What did you use for GND ref. for the meter?

See Pic

2) Which board are you working on, the one on post 1 or post 10?

Post #10...

Probably should start a new thread, eh??

[budm]

Re: Identify The Chip??? Vizio E480i-B2

1) What did you use for GND ref. for the meter?
2) Which board are you working on, the one on post 1 or post 10?
3) If it is the board is post 10, then check the Source resistor R601 to make sure it still show <1 Ohm.

[Michale32086]

Re: Identify The Chip??? Vizio E480i-B2

Thanx for the replies.. A replacement board is only $20... But it would be nice to fix this one..