But the power supply board was clean and all component were ok. It looked to me like a capacitor on the power supply board had burst and spilled electrolyte onto the adjacent PCB. The PCB where the DVI cable gets attached to looked like there was something spilled on, which had dried of course. I would have needed 6 putty knives because there are 6 latches inside the bottom and the top and 4 inside the left and right side. I took the plunge and opened the housing of the 2007wfp (with almost no scratches). Thanks for the tip on opening the monitor cover. I might try your suggestion tr4 if I do not get some more detailed advice. But on the other hand I do not have schematics either. Unfortunately, I do not have access to an oscilloscope and/or logic analyzer anymore since I retired. I would like to check and reseat all connectors and also take a look at the electronics. Of course the problem could also be caused by a faulty electronic part like a capacitor. It looks to me that thermal expansion could be the cause the problem. Tapping with a finger against the back of the cover causes the picture to stabilize immediately, but after a while the problem might come back. When it gets pretty warm, the problem might show up. When the monitor is cold, the problem does not show up.
![dell e207wfp how to open up dell e207wfp how to open up](https://i.ytimg.com/vi/4dF6PjSAj5o/maxresdefault.jpg)
![dell e207wfp how to open up dell e207wfp how to open up](https://c1.neweggimages.com/ProductImage/V036_1_201512192058321275.jpg)
I suspect a faulty connector or a bad soldering point to be the reason. It looks like it is loosing vertical synchronization sometimes (the horizontal lines are all over the place).