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#1 |
Member
Join Date: Jul 2012
City & State: wichita falls TX
My Country: USA
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Posts: 52
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![]() I have a Vizio VX37L that does not have a picture or sound. the Light in front will turn from orange to white when you push power but the tv does nothing. I will also not turn back off, you have to unplug it.
All the voltages on the power supply seem correct so checked the regulators on the main board. they are as follows. Do they seem correct or do i need to change some out? AMC117 f0722f U7 3.21 1.11 0.02 U33 5.09 3.22 1.98 U8 5.11 3.25 2.01 U2 5.09 3.26 2.02 U4 5.09 3.28 2.04 K117515 730 U9 3.21 1.49 0.00 |
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#2 |
Member
Join Date: Jul 2012
City & State: wichita falls TX
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![]() I did test the power supply and i have all the voltages except for A and B they read 0
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#3 |
Badcaps Veteran
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
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![]() If you are reading 0V at A and B, A and B are the control signals generated by the main board to turn on the backlights and Dimming control. Are you getting PS_ON >3VDC?
Can we see good clear pictures of the boards? Is this the same as your TV? http://s807.photobucket.com/albums/y...37L%20HDTV10A/ You voltage reading of the regulators are a little confuse. If you look at the regulator 1117 series with the big tab up Fixed output regulator: Left pin (1) will be Ground Center pin or Tab (2) will be output pin Right pin (3) will be the input pin Adjustable output regulator (it will need two resistors, one is between Ground and Adj pin, another one is between Adj pin and Output pin): Left pin (1) will be the Adust pin. Center pin or Tab (2) will be output pin Right pin (3) will be the input pin This is the way to figure out if the adjustable regulator is good or not: Notes: we are looking at the regulator with the Big tab up (the big tab is tied internally to the center pin). Adjustable regulator will have two resistors attached to it, one resistor (Rfb) is between pin1 and pin2, another resistor (Rg) is between pin1 and ground. Pin3 is an input pin. The voltage between the Adjust pin (left pin) and the center pin (Pin2, output) will always be 1.25V +/- 2% (this is the precision voltage reference), if it is not, it is bad. To figure out what the output voltage should be: measure the voltage between pin 1 and ground and add 1.25V to that number, that is the output voltage on pin 2 but you have to make sure you do have 1.25 between pin 1 and 2 as noted above. So can you label the pins and the voltage you are reading on those regulators? AMC117 f0722f U7 P/N? 3.21 1.11 This one does not look right 0.02 U33 P/N? 5.09 3.22 This one should be 3.3 1.98 U8 P/N 5.11 3.25 looks OK (1.25 +2.01 = 3.26) 2.01 U2 P/N? 5.09 3.26 looks OK (1.25 + 2.02 = 3.27) 2.02 U4 P/N? 5.09 3.28 looks OK (1.25 + 2.04 = 3.29) 2.04 K117515 730 U9 3.21 1.49 looks OK, it looks like 1.5V regulator. 0.00
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Never stop learning Basic LCD TV and Monitor troubleshooting guides. http://www.badcaps.net/forum/showthr...956#post305956 Voltage Regulator (LDO) testing: http://www.badcaps.net/forum/showthr...999#post300999 Inverter testing using old CFL: http://www.badcaps.net/forum/showthr...er+testing+cfl Tear down pictures : Hit the ">" Show Albums and stories" on the left side http://s807.photobucket.com/user/budm/library/ TV Factory reset codes listing: http://www.badcaps.net/forum/showthread.php?t=24809 |
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#4 |
Member
Join Date: Jul 2012
City & State: wichita falls TX
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![]() The picture of the main board in your link is just like mine. same part number and all. I took the readings clockwise. so since the big tab is to the left i guess the way i listed them would be
3 2 1 I do have a PS_On reading of 3.07 which seems a tad low. The part numbers for the U regulators are all AMC117 f0722f except for U9. its a K117515 730 |
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#5 |
Member
Join Date: Jul 2012
City & State: wichita falls TX
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![]() how can i get the U33 up to 3.3 volts?
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#6 |
EVs Rule
Join Date: Apr 2011
City & State: Leeds
My Country: UK
Line Voltage: 230Vac 50Hz
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![]() You should re-test U33. If it still shows low 3.22V, it could be faulty and should be replaced. However, U7 looks worse, as budm pointed out.
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Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead! Free service manuals: http://www.toms-service-manuals.com/ -- 72 LED/LCD TVs, 5 monitors, 28 plasma TVs, and 2 AVR 6.1 amplifiers fixed! -- I repair Pioneer 9G Plasma Main Boards & KRP-M01 Media Receivers (PM me for info) 2 Pioneer KURO 9G, 12 Panasonic LCD/Plasma, 1 Sony LCD, 1 NEC Plasma, 2 Yamaha HTS, 5 Sharp LCDs, 5 Toshiba LCDs, 7 Philips Plasma/LCD, 1 Hitachi Plasma, 11 LG LCD/Plasma, 18 Samsung LED/LCD/Plasma, 1 Thomson Plasma, 1 Atec LCD, 1 Hanspree LCD, 1 Xerox LCD, 1 Harwa LCD, 2 Proview LCD, 2 Hyundai LCD, 1 "Onn" LCD, 1 Grundig LCD, 1 Dell LCD, 1 iiyama LCD, 1 Acer LED, 1 Logik LCD, 1 Baird (China) LCD, 6 Bush LCDs, 22 Vestel LCDs (Best->Worst) |
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#7 |
Member
Join Date: Jul 2012
City & State: wichita falls TX
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![]() I retested it and its 3.22 still. I know theses are all adjustable regulators but i dont think i have any laying around. I do have a few A1-AS1117L but cant find a data sheet to see if they will work.
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#8 |
EVs Rule
Join Date: Apr 2011
City & State: Leeds
My Country: UK
Line Voltage: 230Vac 50Hz
I'm a: Professional Tech
Posts: 32,373
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![]() If they do not have -33 after them or similar they may be adjustable but why take the risk? You could burn the main board due to over voltage. Digikey has voltage regulators for cheap:
http://www.digikey.com/product-detai...4-1-ND/1217057 |
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#9 |
Badcaps Veteran
Join Date: Oct 2012
City & State: Illinois
My Country: United States
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![]() I replaced U7 and U33 both on a 42" Vizio, had low output voltage on U7 and U33 has a high failure rate.. both were same part#, I bought them from Digikey and even got extras since they were so cheap. After replacing them the TV now powers on and works fine.
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#11 |
EVs Rule
Join Date: Apr 2011
City & State: Leeds
My Country: UK
Line Voltage: 230Vac 50Hz
I'm a: Professional Tech
Posts: 32,373
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![]() And shipping is under $3 in continental US, I believe.
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#12 |
New Member
Join Date: Mar 2010
City & State: Chandler, AZ
My Country: United States
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 6
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![]() Had the same happen with another 42 inch vizio (vw42l) and ended up doing the same thing after it still had issues after replacing u33. Been working 3 months now.
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#13 |
Member
Join Date: Jul 2012
City & State: wichita falls TX
My Country: USA
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Posts: 52
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![]() Fixed. Replaced U33 and U7
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