Vizio e470vl has 2 seconds to black

[triplefour]

Re: Vizio e470vl has 2 seconds to black

all pins on u33 are 12.1v except pin 2 and 4 which are 0.02v

[dick_barton]

Re: Vizio e470vl has 2 seconds to black

Use your ohm meter and check resistance for U33
Pin 1 to 8
Pin 1 to 7
Pin 3 to 5
Pin 3 to 6

[triplefour]

Re: Vizio e470vl has 2 seconds to black

all those measured 1.7 on the 2k ohm scale

[budm]

Re: Vizio e470vl has 2 seconds to black

DIM is still connected to the MB, i only pulled out one wire from the connector. the one for pin 13, LAMP
and i have a 1k resistor jumping DIM and LAMP together at cn201

But if the lamp wire is left floating without connected to anything and the rest of the wires are connected I would expect the backlights to come on and stay on also, is that true?

[triplefour]

Re: Vizio e470vl has 2 seconds to black

yea thats what i was hoping too since i seem to remember fixing a tv like that before... but no luck. that lamp pin has to read 2v or no dice. also if i try to jump it from 5vsb, it doesnt work.. so it cant be over a certain v either? without the SM they really got us working blind. i know i read somewhere in a thread on this tv about a guy that said he had jumpered all 3 of them together and was reading about 2v on each and the tv operated normally. DIM, LAMP, and INV on i think it was... but that didnt work for me. i got less than 2v on some of them when i did that

[triplefour]

Re: Vizio e470vl has 2 seconds to black

so...does anyone have any insight as the safety of forcing a 2v signal onto the LAMP pin of the cn201 connector on the PSU? if i can do this safely without having to replace a component i can save everyone time and money.

[vinceroger69]

Re: Vizio e470vl has 2 seconds to black

so...does anyone have any insight as the safety of forcing a 2v signal onto the LAMP pin of the cn201 connector on the PSU? if i can do this safely without having to replace a component i can save everyone time and money.

would using a fusible low amp resistor make it safer? as you friend dosnt want too spend too much if any money on this set.

[triplefour]

Re: Vizio e470vl has 2 seconds to black

in my mind that would make it safer... good idea! but still would like to hear more on the subject! thank you
p.s. the guys gonna have to give me like 20$ at least even tho hes a friend... this is hours already!

[vinceroger69]

Re: Vizio e470vl has 2 seconds to black

if you reconnect the tv wires back up how it should be are all the voltage regulators on the board testing correctly? as one maybe faulty ? causing this issue your having maybe worth a quick test too rule them all out.

[triplefour]

Re: Vizio e470vl has 2 seconds to black

well... i may do that eventually but i really think it cant be the motherboard since its producing the correct voltages...just when LAMP is plugged in, the 2.5v coming from the MB on pin13 drops to 0

[budm]

Re: Vizio e470vl has 2 seconds to black

The 'LAMP ' line input pin on the MB has pull-up resistor to keep it HIGH when there is nothing connected to that 'LAMP' pin, the 'LAMP' pin on the power supply board is connected to a switched Transistor which is turned on if there is LAMP error detected which in turn will keep the 'LAMP' line low. If I am correct the LAMP line should be HIGH when no error detected, right now it is low and it is telling the MB that there is problem with the lamp circuit.

[triplefour]

Re: Vizio e470vl has 2 seconds to black

ok but when i trick it into working, the lamps all light up and i cant see that any one of them is bad... so how do i diagnose from here, whether its a problem on the psu or the lamps themselves?

[budm]

Re: Vizio e470vl has 2 seconds to black

So as I asked post #24, again, do the backlights stay on if you leave the LAMP wire not connected to anything but all other wires connected? We need to verify if the LAMP error is the one that causes the main board to shutdown, and also to verify if HIGH is normal and LOW is abnormal.
BTW, you should spend some of your times tracing out the LAMP pin 13 of the connector CN201 to see where it goes to, looking at it from the pictures from SJ, it looks like it is connected to the Collector of Q709, hard for me to see where else it goes to.
Also, what resistance do you get on the power supply board LAMP pin and GND pin of the connector?
http://www.shopjimmy.com/vizio-0500-...pply-unit.htm#
Vizio 0500-0407-0700 Power Supply / Backlight Inverter

[budm]

Re: Vizio e470vl has 2 seconds to black

ok but when i trick it into working, the lamps all light up and i cant see that any one of them is bad... so how do i diagnose from here, whether its a problem on the psu or the lamps themselves?

You have two choices, try new power supply board, or take the panel apart to really see how all the lamps are.
All the functions of the TV works when the LAMP wire is not connected or tricked, right?
You can also dim the backlights level and the backlifgts still stay on, right?

[triplefour]

Re: Vizio e470vl has 2 seconds to black

ok when i have the LAMP wire disconnected, but everything else connected normally, i still get 2 seconds to black. its only if i use 1k resistor between lamp and dim that i get functionality. this doesnt matter if lamp wire is connected or not. im not at the tv right now but ill try what you said when i get back to it. thanks!
p.s. taking apart the panel is out of the question. no way he's paying me enough for that. such a pain to take apart panels and so easy to break something!

[triplefour]

Re: Vizio e470vl has 2 seconds to black

when i had the tv tricked into working (all pins connected normal or with LAMP wire disconnected only, and 1k resistor between LAMP and DIM), i was able to adjust the backlight via menu