VZ42L No Amber light, no stand by 5v

[windfreik]

I am trying to troubleshoot a vizio that does not go to AMBER or WHITE no sounds/relays, etc. dead.
I want to send the power board or the control board to a shop that will bench test it all and fix for a decent price. If you had to send a board, which board to send first?? I cannot get power to any of the 24v or 5v standby pins on the power board when plugged in. I pushed the reset button on the control board and nothing. Without posting pics and checking all the resistances/etc which board would you send? I realize that i might end up sending both but maybe i will get lucky with the first board I send...
thanks for any opinion or insight
Brett

[tom66]

Re: VZ42L No Amber light, no stand by 5v

Check the fuse... both on the power supply and in the plug.

[PlainBill]

Re: VZ42L No Amber light, no stand by 5v

If the fuse is good, disconnect the output connectors from the power supply and see what happens. You should ALWAYS get 5VSB if the supply is getting power.

PlainBill

[windfreik]

Re: VZ42L No Amber light, no stand by 5v

Ok, let's do this. I should have tried the fuse originally. It was bad. I replaced with new one and now I have SB 5.1v but no 24 volt, still no AMBER, Does not turn on. No sounds, no clicks. I disconnected the power board outputs and still same result. nothing except sb 5.1v. I will get some HD pics uploaded soon, but what can I try next to eliminate the control board?
Thanks.
Brett

[retiredcaps]

Re: VZ42L No Amber light, no stand by 5v

A lot of these Vizios have bad voltage regulators on the main board. U33 seems to be a popular one that goes bad. Either Vizio underspeced this component or got a bad batch.

If that regulator and/or others are bad, the main board will not toggle PS_ON high and the power supply will never start.

PS. HD pics means 2000 x 2000 maximum resolution here and more than sufficient. Note the instructions below and follow them exactly.

[windfreik]

Re: VZ42L No Amber light, no stand by 5v

Here are some pics of the power board. Let me know if i should re-take some, or different angles... Thanks for the help

[retiredcaps]

Re: VZ42L No Amber light, no stand by 5v

Those are excellent focused pics. Now we also need pics of the main/logic board. This is the board where your HDMI, component cables, etc plug into.

PS. This is one of the few TV/models to use name brand japanese quality caps on the power board (Nichicon, United Chemi-con, and Rubycon). Having said that, I have seen the same United Chemi-con cap bloated KY bloat underneath the heatsink by the connector) at least twice in other threads.

[windfreik]

Re: VZ42L No Amber light, no stand by 5v

Here is the main board, bottom and top. I see U33, remind me how to check with multimeter, I am a novice with it, but have tested continuity and volts, but how to check this U33?
Thanks again for any assist\

Brett

[retiredcaps]

Re: VZ42L No Amber light, no stand by 5v

remind me how to check with multimeter

In the picture below,

1) the ground screw circled in black is where your black probe will go. For all voltage measurements, this will be your ground.

2) put your multimeter to 20V DC if it is manual range.

3) With power on, lcd plugged in, and boards connected, you are going to measure all the components circled in blue.

4) The fat tab will be "up" or "north". The left most pin will be pin 1 with respect to "up". Number the pins 1, 2, and 3 (ignore numbering the fat tab).

5) With your black probe on the ground screw (see #1), put your red probe on each voltage regulator starting with pin 1, then 2, and finally 3.

6) Record the pcb designation, part number, and pin voltages. For example, we want to see

U33
part number AS1117-33
pin 1 = 0
pin 2 = 3.3
pin 3 = 5.0

7) Power off and unplug lcd. Wait 3 minutes. Then put your multimeter to 200 ohms and measure the resistance of the 2 fuses circled in red. If they are good, both some measure less than 1.0 ohms.

[windfreik]

Re: VZ42L No Amber light, no stand by 5v

tried all of the tabs you suggested and nothing all zero. Then I unplugged and tried the 2 fuses and only the far left one (vertical) registered (.9). The right one (horizontal) 0. What ya think?

[tom66]

Re: VZ42L No Amber light, no stand by 5v

"0" as in "OL" or "1" on left hand side? Same reading when your probes are not touching?

[windfreik]

Re: VZ42L No Amber light, no stand by 5v

it shows a 1 on the left hand side.... Same as when probes are not touching on that horizontal fuse.

[tom66]

Re: VZ42L No Amber light, no stand by 5v

So, that fuse has failed. You can replace it and if it blows again you will need to locate the fault on the board (or replace the entire board). Those fuses tend to fail randomly, without apparent cause.

Are there any markings on the fuse?

[windfreik]

Re: VX42L No Amber light, no stand by 5v

no visible markings. Is that a fuse I can easily find at radioshack? Or ebay

Also, check out the pins on the far left large voltage regulator.. one of the pins seems to be missing, or designed that way?

[retiredcaps]

Re: VX42L No Amber light, no stand by 5v

no visible markings.

What do you mean no visible markings? It says LF 3A. It is a littlefuse 3A fuse.

Also, check out the pins on the far left large voltage regulator.. one of the pins seems to be missing, or designed that way?

Designed that way.

[windfreik]

Re: VZ42L No Amber light, no stand by 5v

Sorry, I thought you meant marks that would indicate scorch or damage...
I will try and replace and report back.
Thanks again!!

[windfreik]

Re: VZ42L No Amber light, no stand by 5v

will this type of fuse work? http://www.ebay.com/itm/LITTLEFUSE-L...9#ht_500wt_969 or any suggestions off ebay?
thanks

[retiredcaps]

Re: VZ42L No Amber light, no stand by 5v

Get the fuse from digikey.com. Shipping will be around $2.75 USD and you will get it in roughly 2 days with USPS 1st class mail.

Measure your fuse and then search for

littlefuse 3a

on digikey's website. Then pick the right size.

edit: PS. You might want to think about ordering a replacement for U33 at the same time since it has been problematic for others. It should be less than $1 for that part. Until that fuse is replaced, you will get 0.0V DC voltages on all the regulators.

[windfreik]

Re: VZ42L No Amber light, no stand by 5v

parts ordered, will report back!! thanks team!

[Bigredram87]

Re: VZ42L No Amber light, no stand by 5v

In the picture below,

1) the ground screw circled in black is where your black probe will go. For all voltage measurements, this will be your ground.

2) put your multimeter to 20V DC if it is manual range.

3) With power on, lcd plugged in, and boards connected, you are going to measure all the components circled in blue.

4) The fat tab will be "up" or "north". The left most pin will be pin 1 with respect to "up". Number the pins 1, 2, and 3 (ignore numbering the fat tab).

5) With your black probe on the ground screw (see #1), put your red probe on each voltage regulator starting with pin 1, then 2, and finally 3.

6) Record the pcb designation, part number, and pin voltages. For example, we want to see

U33
part number AS1117-33
pin 1 = 0
pin 2 = 3.3
pin 3 = 5.0

7) Power off and unplug lcd. Wait 3 minutes. Then put your multimeter to 200 ohms and measure the resistance of the 2 fuses circled in red. If they are good, both some measure less than 1.0 ohms.

Hi this is my first thread and I figured I should just tag onto someone with similar problems. I have same tv no backlight but my Visio led does goes from amber to white . I have no voltage from 12v or 24v pins on the power supply board. I have done measurements on the above components.
Fuses good

U33
1:2.03v
2:3.28v
3:5.10v

U7
1:0v
2:1.27v
3:3.28v

U9
1:0v
2:1.51v
3:3.28v

U8
1:2.07v
2:3.32v
3:5.14v

U10
1:0
2:0
3:0

U3
1:1.35v
2:2.60v
3:5.09v

U2
1:2.07v
2:3.32v
3:5.11v

I appreciate any input on what to do next thank you guys so much. I am an apprentice electronics technician and would love any help