JVC- GD-V4211PCE intermittent screen problem

[lostin the woods]

I have a JVC GD-V4211PCE plasma monitor, i have a intermittent screen problem.

When turning the Screen on with no signal, i get a series of yellow vertical lines, on the top left hand side of the screen, stopping at the mid way horizontal plane. if a signal is then input into the screen, it splits the image in half, but scrambles it, into two separate sets of lines. one top half of the screen, the other set on the bottom.

At this point it is still showing as a picture but just a scrambled mess of lines, being split into to distinct display patterns of lines.

If you gently hit (not sure how someone can actually gently hit a plasma but there you go) the picture will revert to normal operating for a random amount of time, before it does it again.

I'm thinking its a dry joint / loose cable / connection of some sort, due to the nature of the problem. the Monitor has 4 fans across the back of the set to suck hot air out, yet the screen still gets fairly hot across the back.

I did a search and it turned up another poster with what sounded like the same problem but his / her model was the GD-V4210PZW and never got an answer.

Id like to know what people think about this, as i really don't want to be paying someone just too look at it and tell me what i already think is the problem.

I'm thinking the dry joint / connection problem is somewhere on the upper left hand (if looking at the screen) as it only rectifies the problem if you hit in this area (on the back).

I found a service manual for the GD-V4210 but not the GD-V4211 but it lacks the depth to have a good look inside and know whats what.

Any reply / help would be most appreciated.

Regards

[lostin the woods]

Sorry forgot to add Its a 42" JVC plasma monitor, so you know for quick reference

[lostin the woods]

Right, bit more info see if this rings any bells as to whats going on,

Ive taken the back off of the unit, and removed the digital PB ass'y (code on the back is CKM0355-d01-1) the board is outlined in its component parts, these include scan converter, analog 1 and analog 2, PDP I/F, Panorama, MICON.

In the Analog sections there are two identical chips labeled

103Z01
M52327SP

Reverse board markings give the ID as IC705 (for analog 2) and IC102 (for analog 1)

one in each analog section of the board,

On the reverse side of analog 2's chip, seems too be what can only be described as corrosion of the solder joints. along roughly 9 of the pins down one side. of the 28 (14 pins each side) chip.

This is also right next to the scan converter part of the board and obviousely connected.

Would i be right in thinking this is the source of my problem?

[lostin the woods]

Cleaned up the connection, re-soldered it, checked most of the ribbon cables and cleaned some dust out of the contacts. screwed it all back together and still have the same problem.

So I'm having to put it down to a dry joint.

Ive noticed that when the set is turned on, it now boots with a picture, instead of the lines.

picture turns into lines once the set comes up to temperature.

Anyone got any hints on how to tract down a dry joint and where would be the best place to start looking?

The set does have 3 self diagnostic lights that light up in the case of adverse operating conditions, but they do not light up for this fault.

someone please help I'm at a loss on this one, and shy of calling a specialist in who's going to charge me almost the cost of a new one, any help or reply would be most welcome

[minnie]

Can you post a picture?

[lostin the woods]

sure, just need to charge me camera batteries

[lostin the woods]

working (cold)

10mins later when its warmed up it reverts to this



if the image is moving both sets of bars move independently of each other, as in, if you have a mouse pointer on the desktop when the Monitor is in this state, you can tell whether the mouse is on the top of the screen or the bottom of the screen, on the left or on the right.



Its getting image data, but its just scrambled, the sound is fine though,
The OSD shows as yellow bars, so you can not access the menus.

You can even change aspect ratios with the screen like this and the lines will display the aspect ratio you have changed it too.

[minnie]

Go after the logic board. Too wide spread to be a buffer board.

[lostin the woods]

hmm cant find the logic board in the service manual, though it only shows the underlying circuit boards, and not whats present once you take the back off,

When taking the back off of the monitor, there is a set of circuit boards mounted onto some metal plate raisers, that cover the underlying circuitry, the manual only shows this underlying circuit boards, and not those on top,

I would post the service manual, but not sure if its even legal to do so, though there is a website that offers it as a download for free (makes a change)

Going to have to wait until Thursday when i can get into town and get some sticky tabs, as i need to label the wiring looms that frequent the board. (don't really want to take it apart and forget where the wires go lol)

WIll update you on my progress as it happens

[lostin the woods]

Anyone have a Service manual for this model?

I have the supplementary but need the whole thing with schims.