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Old 04-28-2012, 06:32 PM   #1
RePete
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Default VIZIO VX32L - no pic, no sound, processor reset ?

I have a VIZIO VX32L (Dec 2006) with mainboard 3632-0101-0150 (4A)
that will powerup, VIZIO light lit, screen backlit, no sound, no picture
and can not power down - must unplug. This happened after running the
channel scan and when exiting the menu it locked up. At this point,
could not do anything via the controls and proceeded to unplug it.
Upon powerup it has have the above mentioned symptoms since.

I have verified all the basics, fuses and DC-DC supply and regulator
voltages are good, which I would tend to expect.

I ran across a fix for the processor reset circuit (pull low) that
adds a 10k resistor across pins 2 & 3 of U26. My mainboard has a spot
for U26 (8 pin device) but nothing populated. The device shown in the fix
was a 4 pin device. I have not been able to find a diagram for this
board or a datasheet for the processor MT5372AJ.

Does anyone out there have any info to help me match this fix with my main
board?
Based on how this thing failed it seem like a worth while guess to persue.

Any ideas or other things to check?
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Old 04-29-2012, 05:11 AM   #2
selldoor
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

Can we assume you have tried leaving it unplugged for an hour or unplug the TV completely and let it sit about 30 minutes, then, with the TV unplugged, PRESS and HOLD the power button 30 to 45 seconds.

Is the on screen menu accessible?

If the data on the eeprom is corrupt this can sometimes be reset but its a last ditch
thing to try. Pinpointing the correct eeprom is sometimes difficult if there are a number of similar chips.
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Old 04-29-2012, 06:01 AM   #3
RePete
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

Selldoor:
Yes - I have performed a discharge by unplugging and holding the power button for a minute.

Screen menu is not accessible. Regarding the controls, can only power up, otherwise no other controls function and have to unplug to power down.

A corrupt eeprom is the most logical theory, based on how this set failed.
There are three medium sized SMDs located close to the processor. I ruled out two of them to be RAM. The other device has a label (VX32) on it and when I removed the gum label most of the device numbers are missing. Bad news. As you commented, it is hard to say what device they used. I have found one diagram for the set, but the devices did not match up (processor, ....).

Thanks,
RePete
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Old 04-29-2012, 06:59 AM   #4
selldoor
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

Have you read other posts on this set- type vx32l into the search facility above and
select search by post. U33 seems problematic although your fault does not seem power related , it going off during a scan may have been co-incidental.
There seems to be a lack of really clear photos of the main board, if you could post some. What is the board number of the part you have decided is the eeprom.
Which manual did you download so we do not need to bother with it. In you reply
put "I downloaded xxxxxxxxxxxxxxxxx which is not the same as this set".

Pictures should be (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
http://www.badcaps.net/forum/attachm...1&d=1290283049

http://www.badcaps.net/forum/attachm...7&d=1280167246
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Old 04-29-2012, 10:27 AM   #5
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

My U33 tested fine a lot of the times i tried it . But finally replacing it fixed most of my problems with a vx32l. The problem came back shortly after and i figured it was bad traces to the part all along. You should deffinetly give it a try replacing U33, or soldering a temporary wire directly from the 5v to its 1st pin (source). Because its not always a clear failure on that part.
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Old 04-29-2012, 05:10 PM   #6
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

Yes - I first read the other threads covering the U33 problems and ran all of
those checks before posting this thread. I have included all of my measurements
below. I have also ordered a regulator to replace U33, for good measure.

The circuit diagram that I downloaded is VIZIO L32 HDTV10A_MTK,board 3632-0012-0150. My main board is 3632-0102-0150 (part #0171-2272-2174).
I am including pictures of the main board, hopfully the resolution is ok.

The device that I believe is the eeprom in U16, just left of the processor
and has an orange line across the top.


Component SB out SB in ON out ON in
#1084
U10 0 0 2.61 5.07

#amc1117
U7 0 0 1.24 3.31
U9 0 0 1.50 3.31
U33 0 0 3.32 5.08
U8 3.33 5.15 3.33 5.12
U2 0.12 0 3.31 5.08
U4 0 0 3.31 5.08

#7805CT
U3 0 0 5.02 11.91

Fuses
F1: 11.93V ON
F2: 5.15V SB

Connector
J1:
Pin 1 3.15 PWR ON
Pins 2,3,4,5 11.93V PWR ON
Pins 9,10,11 5.15V SB, 5.15 PWR ON
Pin 12 1.58 Pwr ON
Pin 13 3.67 Pwr ON

Connector
J6:
Pin 1 5.89 Pwr ON
Pin 2 5.90 Pwr ON
Pin 3 5.92 Pwr ON
Pin 4 5.86 Pwr ON
Attached Images
File Type: jpg P1000603left.jpg (475.5 KB, 52 views)
File Type: jpg P1000603right.jpg (469.9 KB, 46 views)
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Old 04-30-2012, 03:57 AM   #7
selldoor
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

U16 looks a bit complex for an eeprom - have you tried cleaning the surface with isopropyl alcohol.
Pics are not quite clear enough for troubleshooting U11 or U23-25 are more
like what I have seen as eeprom chips - what are their part numbers.
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Old 04-30-2012, 08:24 PM   #8
RePete
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

The alcohol worked on U16.
U16 MXT064021 9LV320CTTG S565200

Below are the part numbers of the other chips.
U11 74RC00
U23 ATMEL640 24C02BN (2K Serial EEPROM)
U24 PISC 3257QE Z0644
U25 ATMEL632 24C02BN (2K Serial EEPROM)
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Old 02-20-2013, 09:59 AM   #9
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

what about when the board have the stand by power but no power on ? i prest the botton power but nothing happen model: 0171-2272-2174 some one know ?
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Old 02-20-2013, 01:41 PM   #10
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

"U2 0.12 0 3.31 5.08'
Does not look right, the output should be 1.25 + 0.12 = 1.37V (Adjustable regulator, the out put will always be equal to 1.25V + PIN 1 (ADJ pin) = output at pin2.
The way you show the reading is a little confuse also since you are showing 4 readings per 1117 IC, the big tab is connected internally to the center pin (output pin).
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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

Last edited by budm; 02-20-2013 at 01:45 PM..
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Old 02-20-2013, 02:54 PM   #11
cashkennedy
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

The posts your replying to budm are over 8 months old.

Inregards to the new post by yonyako, you should follow the basic troubleshooting steps for any LCD tv, and the diagram in the service manual for diagnosing the TV.

The most common part to fail on these sets are dc-dc regulators, but you should do the basic first steps to troubleshoot a TV, such as measuring the output voltages from the power supply with a multimeter. A basic guide to troubleshooting tv's is attached to the thread at this link:
http://www.badcaps.net/forum/showthread.php?t=25810
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Old 02-22-2013, 02:55 PM   #12
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Default Re: VIZIO VX32L - no pic, no sound, processor reset ?

thank you so much for you help
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