Re: Panasonic Viera TC-L32U22 no picture
but at this point I am not seeing any voltages leaving the a board and going to the screen. I usually think cause and effect (broken due to transport), but perhaps it was coincidence....
Redrum
Member
Last Activity: 12-13-2018, 10:35 AM
Joined: 05-03-2015
Location: Buffalo, New York
-
Re: Panasonic Viera TC-L32U22 no picture
Yea, that's what I originally thought but I did reseat all connections. After that all of this testing has taken me down this rabbit hole where I know what I am seeing isn't right, but not sure if I am seeing the smoke or the fire.
Jim...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
OK, I have managed to convince myself of one thing. I don't understand the power distribution scheme or mechanism, so I don't understand what's going on, what controls what.
I had assumed that the PS board produces the 12v which IC4800 converts to AVDD13.7V and DVDD2.5V. I had further assumed that PANEL_VCC_ON and VDD25_EN are the respective enable lines to allow IC4800 to generate the voltages.
I am assuming (for now, by inferring from the block diagram) that PANEL_VCC_ON controls AVDD31.7V and VDD25_EN controls...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
got it: power off (unplugged), standby (plugged in wait a few seconds), power on (press power, wait for the "click" and the backlight glow).
Understand state changes.
I'll take a few more thorough measurements later today...
JimLeave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
I'll included the sos when I remeasure later today....Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
There is no part number on the IC itself.
The IC part number as listed in the service manual is C0DBZYY00343. A search of this returns nonspecific "panasonic part". That's why I said "Asic?". You can see this part number on the schematic portion of image I supplied as well.
Another part number listed on the schematic image is BD8191MUV-HVE3, which returns that is is made by Rohm (and others) but I could not find anything more specific.
I have done all measurements at power on (press...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
ok, here is the latest. I think I have been chasing down the wrong path, but it has been a fun chase.
From the beginning I was looking for a fuse link to supply 12 to the panel. I found that voltage was present on the main board, but not the panel.
However, I think I was off in chasing down a fuse in the supply path. I put together a combo image of the block diagram (on the left) and schematic (on the right) sections of the area I have been focusing on. See the attachment.
I have found that the...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
ok, haven't spent any time on it today. I'll start tracing via continuity tests. I'm not thinking any more pictures are going to help because I don't have a good closeup lens, and aren't the res/size of jpegs limited on this forum?
Replacing the board isn't really much of an option at any kind of $ because you can get 32" sets new for a little over a hundred, and I would be buying a board not knowing for sure it's the problem, and even if it was, why did the board fail in the first place?
Compounding it's fate...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
Hi, thanks for sticking with me. I appreciate it. I don't really have a use for this TV now, but I get a kick out of fixing things. Having said that, if I do give up at some point, no biggie. I have alot of other things on the "project bench" waiting.
First, lets agree that we are both talking about the A Board, not the integrated Tcon board on the panel. I am not seeing voltage leave the A board.
I'll take some full board shots in a little bit, both sides, and also the area around IC4800 closeup.
...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
I have looked on both sides. How do they differ in appearance? color? indicator? there are no component numbers on the boardLeave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
ok, here's where I am at.
I could not get any significant voltage readings at the panel ribbon connector, specifically I could not find AVDD at pins 72-76, it was easy to probe.
I then went back to where the power supply board (P Board) supplies the A Board. See the attachment. I found 12V at the connector, but when I went to IC4800, I couldn't find it present at the IC and connected C's and R's. Note that there is a fuse, PA4800 which may be the culprit, but I can't fine it at this moment. Note that there is...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
Ok, back to looking at this again...
I will look to probe the voltages but the following has directed me back to looking for a tcon fuse again.
I found the tcon board number MDK 336V-0 W (see image). I searched this forum with this number and found this:
[url]https://www.badcaps.net/forum/showthread.php?t=71542&highlight=mdk+336[/url]
which lead me to this:
[url]https://www.badcaps.net/forum/showthread.php?t=32742[/url]
The last thread is for a panny 32" but...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
thanks. Just a FYI, I won't post back for a couple days, I have to go out this afternoon and have an all day thing tomorrow. Once I get the time I'll check and post back.
I appreciate it.
JimLeave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
good morning,
I really don't have any way of probing that fine of a pitch on the connector. There must be a test point somewhere.
I have attached a picture of the label on the panel.
Also, I have attached a screenshot of the block diagram to the panel (from the service manual), and two screen shots of the schematic for that 80 pin connector. perhaps if you could point me to what I am looking for, I can trace back to find a tp on the a board.
I ask because I see alot of reference...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
thanks, this is the best I can do. I don't have a macro lens. Took this full res, then cropped in photoshop.
what am I looking for?
In everything I have found, this TV has a P (ps) board, an A board, and two other little boards for the input/controls and the IR. The panel seems to be treated as an assembly. If you look at the manual in one of the first posts, the block diagram represents this. In searching for parts, only the A, P, and two little boards are represented.
So, I am thinking if the...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
ok, I originally took the pictures to say "is this where you mean?". I'll be happy to take all that are needed. Then, on trying to load them (as a jpeg) to the website it said invalid extention for png"????
Anyhow, here is another shot of the area. I see no fuses on the entire board, just smt components.
anyhow, as a reminder, solid LED on (not flashing), no picture, no sound, but I see backlight
Jim...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
thank you, please see the pictures. Is this what I am looking for? The second picture just shows the portion of the board where the ribbon from the A board connects.
I'll look the board over next, but if you have any guidance, that would be great
Jim...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
Hi,
thanks for the tip. But, I am not finding a tcon fuse. The only fuse I see is on the line. I have attached a snapshot of the block diagram for the service manual which show tcon12v being sourced by DTV12.
See attachment, am I looking in the right spot? P board or A Board?
Jim...Leave a comment:
-
Re: Panasonic Viera TC-L32U22 no picture
sorry to bump this 2 1/2 year old post, but I have the exact same TV with the exact same problem - Power LED on solid, no blinking, no picture, but there is a backlight (you can see the backlight level change on input change), no picture, no sound**
** I have not tested sound on all inputs, just for the hiss on the RF input.
Was this issue ever resolved for the unit in this thread? I thought I would ask before I button it back up and take it to electronic recycle.
JimLeave a comment:
No activity results to display
Leave a comment: