Vizio P502ui-B1E No power on, led blinks once when pwr plug is inserted into outlet

[Doc38343]

Said he watched it day before, next morning nothing. I noticed that when i plugged it into the power the led blinked on just once and then nothing.
I checked the power supply and found a shorted SMD diode. It was position D9104. I had also removed a thru hole diode D9100 but it checks good out of circuit as well as Q9111. I at first thought the transistor was bad but it tests good out of circuit.
I cannot get a data sheet for this diode D9104 it has PJ4256 at top and MB810 below. I get nothing from a google search.. was hoping someone could point me to a replacement...
note- it is a rather big SMD but I think the PJ is the package but hey i don't know much about the SMD parts size identifiers and tend to get the wrong ones half the time.
I believe this single diode is the whole of the trouble...

Thanks in advance.

[budm]

Re: Vizio P502ui-B1E No power on, led blinks once when pwr plug is inserted into outl

Can we see straight shot pictures of top and bottom side of the board so we may be able to figure out the function of that diode?

[budm]

Re: Vizio P502ui-B1E No power on, led blinks once when pwr plug is inserted into outl

Looks like this one.

[Doc38343]

Re: Vizio P502ui-B1E No power on, led blinks once when pwr plug is inserted into outl

Everything looks like it is correct... thanks! Now I just have to find one to buy..
Size is spot on in the datasheet.
Thanks

MB810

[Doc38343]

Re: Vizio P502ui-B1E No power on, led blinks once when pwr plug is inserted into outl

Attached photos, top and bottom - with and without marks (red arrows)

[budm]

Re: Vizio P502ui-B1E No power on, led blinks once when pwr plug is inserted into outl

D9100, D9104 are connected in parallel, but the one with the lower Vf will conduct and have most of the current flowing through it, it is wrong to use two diode connected in parallel, especial they are not the same spec and no balancing.
That is the 12VA standby power supply section.

Vizio ADTVE2425XB6 Power Supply for P502UI-B1E
http://www.shopjimmy.com/vizio-adtve...pply-unit.htm#

[Doc38343]

Re: Vizio P502ui-B1E No power on, led blinks once when pwr plug is inserted into outl

D9100, D9104 are connected in parallel, but the one with the lower Vf will conduct and have most of the current flowing through it, it is wrong to use two diode connected in parallel, especial they are not the same spec and no balancing.
That is the 12VA standby power supply section.

Vizio ADTVE2425XB6 Power Supply for P502UI-B1E
http://www.shopjimmy.com/vizio-adtve...pply-unit.htm#

Sometimes I think these companies design boards to deliberately fail.
Thank you for your assist...

[Doc38343]

Re: Vizio P502ui-B1E No power on, led blinks once when pwr plug is inserted into outl

Ordered the power supply board. Installed it and all is well.
Thanks!
Note: never did find where I could order the smd diode. Found one i think was equal but with shipping it was 2 thirds the cost of the entire guaranteed board replacement so I went with the sure thing in this case.