Vizio JV50P – Sound but no picture

[ChrisV]

I was really hoping to solve this problem by just looking through the many threads in this forum that have been answered but unfortunately, after hours of research, trial and error, I've struck out so far. I am humbly asking for a little guidance.

The TV powers up with or without the remote. The VIZIO insignia lights up and turns to white when the set is turned on. After 30 seconds, I can get sound from my input but no picture. The screen is 100% black although I have seen the bottom half of the screen or small strips of the picture horizontally across the screen on a couple of attempts.

PSB is good. The voltages are right on target

I replaced the YSUS card and the Y buffer boards with a good used set. This didn't solve the problem. I may have thrown parts at this TV before I fully thought about it.
The voltage draw does not change when either of the Y buffer boards are disconnected. Disconnecting either of the boards has no affect on the display

There is no change to the monitor display when disconnecting the ZSUS
There are no blown fuses. There power is good across all of the fuses.

I guess at this point, I'm wondering about the control board.

Any advice would be appreciated.

[ChrisV]

Re: Vizio JV50P – Sound but no picture

Still hoping that some kind person will chime in and help me out with this. I'm attempting to fix this TV for a family member and hate to give up. I'm going to give a little more information here and hope for a few suggestions
PSU voltages:
VA - 65v
VS - 193.1
M5V - 5V
I've completely isolated the Y and Z cards separately and checked the voltages on the PSU. There was no change in voltages on the PSU with either of them isolated. No sign of backlight or picture with either of the boards isolated.

I've checked the resistance on each of the fuses. They are good and they have 193V across them while the set is powered up.

At the bottom right side of the power supply, there is a connector that leads to the main board (The board that the inputs would plug in to). I've attached a picture of the connector. Here are the voltages tested at the connector
16.5v = 16.4v
Gnd =
12v = 11.8v
Gnd =
5v = 5v
5v = 5v
Gnd =
Gnd =
5v_Det = 4.8v
RL_On = 4.5v
M5v_On = 5.0v
The 5v_Det and the RL_On were a little low. Can this cause a problem?

I have read some threads on this forum that explained how to perform a test while jumping a couple of positions on the control board. I believe this test will allow a screen to run in some sort of test mode. This could indicate a bad main board? I'm having a hard time finding specifics for next steps for this vizio tv.
Thank you for reading and helping out.

[ChrisV]

Re: Vizio JV50P – Sound but no picture

I'm still working through this problem. Even though I haven't gotten anyone to reply, I'm very thankful for all of the information that is available on this forum. I'm going to update my progress as I work through this.

Using the service manual that is available through a member of the forum, I've focused in on the Y-SUS card. I've already replaced this card with a used card along with the upper and lower buffer boards. I made an assumption that the replacements are all good. In fact I now believe that is not the case.

With both buffer boards in place, there is no voltage readings at the -Vy or VSC test points.
If I do the same test with the upper buffer board removed, I am able to get voltage at both test points. This leads me to believe the upper buffer board is bad?

I'm trying to understand the correct DMM setting for taking the -Vy test point and will try to adjust to the target on the label. Looks like a negative number on the label. (I'm more of a mechanical person. Learning as I go)

I am also trying to find the targets for Set_up (Currently 15.8v) and Set_Dn (currently 13.4v)

The screen is still black with the upper buffer board removed. No signs of a picture when looking closely with a flashlight.
I'm going to make sure I get all of the things listed above squared away before I continue on. Possibly going to buy another upper buffer board.

[ChrisV]

Re: Vizio JV50P – Sound but no picture

Update...
This TV is once again alive and well. After many hours of research on this forum, youtube and google I was able to fix the TV.
The problem to start was bad capacitors on the power supply. After I replaced the capacitors, the power was restored but there was no picture.
I found the buffer boards to be shorted so I replaced the Y-SUS card and both buffer cards. Still no luck..
After going through many hours of trouble shooting the main board and control board voltage regulators and finding no problems, I went back and looked again at the buffer boards. At this point, I realized that I hadn't plugged the ribbon cables completely into the buffer boards. I guess you really need to get them in there.
End result...It started right up and looks great. Looks like the power supply failure must have taken out the Y-Sustain card and/or buffer cards.
I never did get anyone to jump in and help me through this, but I really did learn more by doing the research myself.
I fixed this TV for my brother that couldn't afford to buy a new TV. I've found another plasma on Craigslist for $20 that I will attempt to fix for fun.
So, thank you to those of you that have answered and worked through problems on this forum. You probably helped me out without even knowing it.

[PlasmaRon]

Re: Vizio JV50P – Sound but no picture

Congrats on getting that set going! It's a great feeling to be able to bring some expensive chunk of electronics back to life!

[mmartell]

Re: Vizio JV50P – Sound but no picture

Good job ChrisV way to hang in there.

[ChrisV]

Re: Vizio JV50P – Sound but no picture

Thanks guys