e420vse no standby light

[kornwood]

found one of these at a recycling place I have done some testing on it .it dosent display standby light
but has 3.3v standby going to mainboard one fuse was bad f2 on mainboard which is 12v power
on inital plug in no standby power light only have 3.3 coming from power supply pson and on/off have 3.3v also if I press power button the power supply turns on and sends 12v to mainboard but still no light on vizio logo also I dont get 24v to led panel but I do have 3.3 going to it from power supply

[tom66]

Re: e420vse no standby light

Vizio?

[kornwood]

Re: e420vse no standby light

yes sir its a vizio e420vse. led tv
ill post pics of the boards later

[ecking767]

Re: e420vse no standby light

found one of these at a recycling place I have done some testing on it .it dosent display standby light
but has 3.3v standby going to mainboard one fuse was bad f2 on mainboard which is 12v power
on inital plug in no standby power light only have 3.3 coming from power supply pson and on/off have 3.3v also if I press power button the power supply turns on and sends 12v to mainboard but still no light on vizio logo also I dont get 24v to led panel but I do have 3.3 going to it from power supply

I came across 10 of these Vizio E420VSE and all had the same problem, a fail LED driver board, check the LED driver board fuse and goes from there. If the fuse isn't blown then check the IC chip HAI 7207PC to see if it getting too hot to touch when you power on the TV

[kornwood]

Re: e420vse no standby light

ill try that shortly and on these newer tvs you can have a symptom that makes you think its one thing but in the end could be something else because every component has to be hooked up and working
ive also checked all the 1117's that are on the board
and they all check out good inputs 5ish and discharge is what there marked 33 meaning 3.3 and 12 meaning 1.2 on the chips after 1117
now ive read that other older model vizios lost there flash in the spi chip could I hook up my blackcat usb
and dump the flash to verify its there and mot blank and to just have it

[kornwood]

Re: e420vse no standby light

ok so that hai chip is hot after a min or two the fuse is good
theres a short from source to ground on the 2 aod4454
chips

[ecking767]

Re: e420vse no standby light

ok so that hai chip is hot after a min or two the fuse is good

Ok, here is the good and bad, the good news is you found the problem with your LED HDTV, the bad news the HAI 7207PC is completely out of stock world-wide. I have been trying for months to get the IC chip and I have not been successful.

[kornwood]

Re: e420vse no standby light

ok next question is that chip used in another board
and thank you

[ecking767]

Re: e420vse no standby light

ok next question is that chip used in another board
and thank you

I haven't came across the HAI 7207PC in any other Vizio LED TV, I have three of these E420VSE, I can't fix them until the 7207pc is available. A seller on eBay have a fix but he sold out for now.

[kornwood]

Re: e420vse no standby light

theres a short from source to ground on the 2 aod4454
are we sure these are not the issue
and ive contaced a few people about those chips and like you said there are none available
the guy on ebay said he will have some in a week or so but who knows but im gonna remove those 2 chips and test them properly

[tom66]

Re: e420vse no standby light

Source is often grounded on a MOSFET. Not always, it's topology dependent, but often.

[kornwood]

Re: e420vse no standby light

ok thanks
that one guy on ebay that sells that one thing is that alternate power when the power supply dies or for what we need
http://www.ebay.com/itm/vizio-42-e42...item2c6ca32996

[kornwood]

Re: e420vse no standby light

heres a pic of that led board and the bad chip circled

[kevinm34232]

Re: e420vse no standby light

So does that ebay board fix the issue?

[Mr Bill]

Re: e420vse no standby light

Might be worth sending him a message asking if he is going to continue selling these. If you look at his feedback i think the 2nd or 3rd one down the buyers says it's still working after a week.

[kornwood]

Re: e420vse no standby light

he said he will have more in a week or so

[kornwood]

Re: e420vse no standby light

ok with the driver board unplugged 24 volt isnt turned on when the power putton is pushed 12 volt comes on to the mainboard actually even pluged in it isnt there so theres only 3.3 going to driver board

[skyanchor]

Re: e420vse no standby light

As far as the $50 eBay board, I sent the guy a couple of messages, and he replied that:

1. "this new power supply is only using the old card to connect to power and the leds the old board is nofuntional", and
   
2. "yes the the ambient light sensing option will not work with the new power supply."

His power supply looks like it could be identical to one you can buy from China on eBay for $6.50. It looks like he resoldered/reconfigured it slightly so that its height is reduced in order to fit inside the TV:
http://www.ebay.com/itm/1-DC-DC-Boos...item4d05c1bbdc

[ecking767]

Re: e420vse no standby light

As far as the $50 eBay board, I sent the guy a couple of messages, and he replied that:

1. "this new power supply is only using the old card to connect to power and the leds the old board is nofuntional", and
   
2. "yes the the ambient light sensing option will not work with the new power supply."

His power supply looks like it could be identical to one you can buy from China on eBay for $6.50. It looks like he resoldered/reconfigured it slightly so that its height is reduced in order to fit inside the TV:
http://www.ebay.com/itm/1-DC-DC-Boos...item4d05c1bbdc

I have this LED TV on my work bench and there is 83volts on the output where you connect the LEDs, so he had to step-up the output voltage for those LED's to work correctly

[skyanchor]

Re: e420vse no standby light

I have this LED TV on my work bench and there is 83volts on the output where you connect the LEDs, so he had to step-up the output voltage for those LED's to work correctly

Thanks, that's very useful information. In that case, here's a higher voltage version I found on eBay for $14 with free shipping:

100W DC-DC boost step up converter in 10-32V high voltage out 60-97V
http://www.ebay.com/itm/100W-DC-DC-b...item27c901e470