Akai pdp42z5ta, vertical red lines, flashing menu

[johnboy1313]

Picked this one up in a package deal. The input selection menu flashes rapidly, like in this thread with no solution.

https://www.badcaps.net/forum/forumd...aysprune=&f=31

I've read and am assuming that the red lines mean the panel is likely bad but as I watched this video that I made, I realized that it's possible that the red lines aren't visible through the menu so maybe the panel isn't bad after all. This one doesn't have a stand, so I haven't gotten the back off yet.

https://www.youtube.com/watch?v=Ai0Syup4438

I really just wanted to hear some opinions on the red lines before I spent any time on it.

[tom66]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

The blue screen is usually generated as part of the main menu -- so it could be a bad panel or bad memory. I would say it's unlikely to be a bad panel, because it would be unusual for only the red lines to appear. Normally you'd get black lines or multicoloured lines.

[johnboy1313]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

Any idea where I should start to fix this? I have a Vizio with the same (for the most part) innards that I can swap boards but I'd at least like to have an idea which board to try first.

[tom66]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

I think the vertical lines and flashing input are separate faults.

First you need to play video on the screen. If the lines cover the video then the fault is with the control, panel or main board. If not it is on the main board only. Also, try unplugging the button panel to see if the menu stops flashing.

[johnboy1313]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

I just wanted to follow up with this. Unfortunately, I sold the Y-SUS and buffer board before I got the answer. A plug on the cable from the control to the main was broken pretty badly, so maybe that had something to do with the lines, who knows. I'm going to stick this one in the back room and hold onto it in case I ever need to use the PDP42X3 panel.

[johnboy1313]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

I'm bringing this one back to the top. I found another one locally with what i believe to be a bad panel (one third of the picture is gone but theres no sharp edge between good pic and no pic). I got it last night for $30. The way I see it, even if both panels are bad, I can hold onto the internals. I'll keep you updated.

[johnboy1313]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

Well, the lines and flashing menu are definitely unrelated. I got the y-sus, buffer, and main swapped from the other set. The digital board I verified was good in the Vizio a couple weeks ago. The flashing menu is gone, but the vertical red lines are still there. Now that the menu is no longer flashing, it's easy to see that the red lines run through the menu as well. I'm guessing that this one's got a bad panel too.

[johnboy1313]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

I should add that the lines aren't there on a black screen or when the panel primes. When the screen is black and the menu is on, you can only see the lines on top of the menu.

[tom66]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

Can we see a picture of the fault with the donor TV? The lack of a sharp cut off is usually a sign that it's not a defective panel...

[johnboy1313]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

I'll have to swap the boards back. For now, it looks like this, but covers nearly a third of the screen. There is a picture though and no buzzing.

http://cdn.avsforum.com/6/60/600a661...ach178458.jpeg

[tom66]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

Ah OK then, though I have seen a dim picture with portions missing being a Z-sus issue.

[johnboy1313]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

Is there any likelihood that the x buffers on the bottom could cause the vertical lines?

[tom66]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

Pretty much zero. The x-connectors pump serial data into the driver ICs which then decode this to drive the columns. What I find surprising is that only the red lines would get stuck.

[johnboy1313]

Re: Akai pdp42z5ta, vertical red lines, flashing menu

With a video source connected, a blue background produces pink lines, a light background produces blue lines, a red background produces black lines, and a dark background (black, dark green, brown) seems to have no lines at all.