VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

[aaronwt6]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

The capacitor I'm talking about is on the main board. All I'm saying is make sure the power supply is working correctly before you start changing things. Because the 5th one of these I had was acting the same way, but it was a power supply issue. Supply was only producing 5VSB and nothing else.

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

well it seems like ive got power supply issues for now, but when i get to the motherboard that is good to know

[budm]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

OK, take the resistance reading between Ground pin (Pin5) and all other 7 pins and repart the readings, make sure to show if it is in Ohm, K Ohms, or M Ohms.
I.E.
Pin 5 (Ground) ref point and
pin1 = xxx Ohms
pin2 = xxx Ohms

Once that is done, then we will be taking the DC voltage test next using the pin 5 (Ground as the ref point, just be careful not to let the probe slip, you will have to figure how to run that power supply board with all the connectors connected and power up with the board sitting with the soldered side up.

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

pin5 ground
pin1=3.39k ohms
pin2=inf
pin3=50.9k
pin4=1k
pin6=8.88k
pin7=4.66k
pin8=1k

cant take the DC voltages yet because i would have to put back these caps. which according to their datasheets, may be failed. should i just put back the failed caps for now to test the DC volts on the SMPS or would it be worthless because we know the caps are bad and they would be throwing off the readings?

[budm]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

Just put the cap back in for now, just want to see what kind of voltage you have on the pins, looking to see if there are any fluctuating voltages on the pin, especially the VCC.

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

well great. i just about had all the measurments done. was measuring the last pin and my stupid hand slipped and i heard a pop.
the fuse is still good, but now i only get 160v on the main filter cap.
so mad at myself right now

and there are no volts to the SMPS IC now

here are the readings i had before the disaster

pin1 BNO = 4.66v
pin2 COMP = 0v
pin3 Latch = 4.66v
pin4 CS = 0v
pin5 GND
pin6 OUT (this is the one i was trying to measure when i messed up so i didnt get it)
pin7 VCC 14.something volts
pin8 0v


now i get 0 for all of them. im thinking i fried the chip. is it possible i fried more than just this one chip?

i no longer get the white vizio logo
and i no longer get 5v standby

tell me theres still hope

[budm]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

Well, we have to get the 5V STBY back first. It may be time to get the replacement board.

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

i was afraid you'd say that. do you think it could have fried more than just that one IC?

numbers on the board are
715G3418P01W30003U

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

cheapest i can find is 30$ shipped ... i'd still like to try to fix this board, as this is less about fixing tv's now as it is about learning everything i possibly can about these components and the circuits that no doubt are similar on other TV's. but i understand if you dont think its worth it to help on this one anymore, then i may just have to bench it for now until i learn more...or cross my fingers and replace that IC and hopefully be back where i was.

but why does digikey not have it?

http://www.aliexpress.com/item/hot-o...801154218.html
i found it here but i'd have to buy 10 and pay shipping so 15$

is it a common chip? could i find it in another TV? or is it possible someone here had to buy it before and has a few lying around?

[budm]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

Well, you can check the voltages and see if you still have the same voltages as in your POST 3 which is the standby power supply section.

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

ok i get 5v on pin 2 but zero on all the others. actually pin 5 shows a 1.3 but then it drops down slowly to under a volt and then starts jumping around between zero and less than 1v

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

im thinking of buying this power board but the numbers are slightly off. it comes from the same tv and looks the same as my power board though. how would i know if they are compatible?
http://www.ebay.com/itm/Vizio-VA26LH...item46204d22e7


715G3418P01W30003U - my original board
715G3418P03W30003M - this new board

[selldoor]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

Could be the same guy as in post 61 - ask him?

[selldoor]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

but why does digikey not have it?

http://www.aliexpress.com/item/hot-o...801154218.html
i found it here but i'd have to buy 10 and pay shipping so 15$

is it a common chip? could i find it in another TV? or is it possible someone here had to buy it before and has a few lying around?

Available on ebay 1 2 or 5

http://www.ebay.co.uk/itm/2PCS-PWM-C...item3cc7bcf1e5

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

i swear when i looked on ebay i couldnt find it...but there it is! thank you. and ordered.

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

well i finally got the chip and got around to installing it... first time replacing a Surface mounted IC so maybe i did it wrong, but i was hoping to be back where i started...no dice. same 160v on the main filter cap.. no v on either side of the fuse.... and i havent checked yet but i'd bet im not getting any volts to this chip either. how can i tell if i damaged the chip while installing it? also is it possible i damaged the traces? or is it more likely that when i messed up earlier and shorted out the chip that i shorted out some other chips as well?

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

measuring resistances after the chip is installed i see the same as in post 64 except for on pins 6 and 7
pin 6 has .03 ohms resistance to ground
and pin 7 is infinate.

is it possible i didnt solder it correctly?

testing the new chip before installing it, and testing the old chip after removing it (the one i think i fried) the resistances were all infinate except between
5 and 6 which is around 150k in both chips.

is there any way to know if an IC is fried besides putting it in circuit and testing DC voltages?

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

after retouching with the soldering iron, i get the 4.6kohms resistance on pin 7
and now i get 26 ohms resistance on pin 6...
plugging it in i still get no vizio light. and on the power connector that goes to the mainboard, i get 1v on all pins except grounds...
160v across main filter cap and in a few other places (diodes n resistors)
...
theres probly no way to tell what else i fried when the probe slipped.
lesson learned. just gotta be more careful.

probly just need to buy the board already unless anyone has a bright idea

[triplefour]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

so i cant seem to find the right board 715G3418P01W30003U
how can i tell if another board might be compatible?

[SmartSped]

Re: VIZIO VA26LHDTV10T has white vizio logo before pressing power on. no backlight.

I know this is an old thread but I just wanted to touch on what Aaron said back on page 2. I checked all my voltages and checked all of the voltage regulators and everything looked good so I changed out the cap that Aaron referenced and it fixed the issue I was having which was a white standby light with no response from the power button. For reference sake, the cap in question is a 330uf 16v and is labeled C117. My tester said the value on the old cap was 347uf.

Thanks!