Smartboard Alignment Problem

[will_]

This is a very interesting thread. I don't have any solutions but a few thoughts:

 

The image in the original post shows a number of different types of "jaggedness" - some lines wiggle up, some wiggle down, and some wiggle more than others. If you consider just the offsets caused by the wiggles, they form a sine wave: slightly down, very down, slightly down, slightly up, very up, very up, slightly up. It sounds as thought you've already reached the same conclusion but this suggests to me that the problem is almost certainly caused by interference from an analogue signal (and even "digital" signals are ultimately analogue by the time they reach the wire).

 

Andytown, you could buy an ordinary plug and screw the wire into the earth terminal properly, running it through the strain relief as you would normally do with a mains cable.

 

There has been a lot of discussion involving earthing things, and I think you're probably heading in the right direction by doing so. However, it might be worth ensuring everything is earthed in the same place. Minute differences in earth potentials can cause small currents to flow between them ("earth currents" or "earth loops"), which are what can cause the humming in audio amplifiers and may well also be the cause of your problems.

[agentz]

have attached some photos, first one is before I did anything, brand new laptop and projector... quite an old board. But like I said with the combination of new 2 pin power adaptors there was no earth. The second photo shows the earthing cable attached to the vga lead... the third one then shows the other end of the earthing kit attached to the top pin of a metal 3 pin plug. The last photo then shows the result... Perfectly smooth and as the alignment should be..

 

Hi Neon and everyone else with the same issue.

 

Not been on here for a long time but I just want to give you a huge thanks for this solution - I've had a couple of users report the jaggy line problem after having new NEC projectors installed to replace failed Hitachis. I was kinda sceptical the first time when a teacher insisted that the problem only started after they got their new projector installed but after finding this thread and earthing the VGA cable as suggested the problem went away

 

I hunted round the school and found a Dell power supply with an earthed mains cable and attached it to their port replicator and the problem got significantly better but didn't go away completely. I'm now speaking to our electrical maintenance team to get a workable, easily deployed solution as we're just about to place an order for a couple of hundred NEC projectors to replace ageing Hitachis and I can guarantee more teachers are going to have the same issue.

 

So, once again thanks to Neon and others who helped me with this issue

[neon]

Glad all this has helped others. Also the earth cable can be ran from any end of the vga... mine are all ran from the faceplate 1.5m to the nearest plug. saves running it in the roof space like the first one i did

[mr-man]

Thank youy to all the advise given, i am certainly going to try the earthing idea as i have tried just about everything else. I will let you know the outcome.

[Jac]

Hello

we have found that if you attach a earth wire to the projector VGA port and connect it to something metal usually in the ceiling if its mounted this solves the problem of wavy lines.

[Huber]

Can someone tell me what kind of "earth cable" they used? Maybe a link or a picture?

[justgenius]

Can someone tell me what kind of "earth cable" they used? Maybe a link or a picture?

 

Hi, I cut a length of cable from a regular PC lead, which in Europe is 3 core cable - live, neutral and earth. Any one of those 3 cores would do the job. I crimped on 2 terminal connectors (an end piece with a hole in it that is about 4mm in diameter). You can then screw one end of that cable onto one of the screws around the edge of the whiteboard, and screw the other end in using one of the screws holding the SC6 controller board. So, basically you have a piece of cable about 5" long, touching the SC6 controller board and touching a screw which makes contact with the metallic board. That's it.

[Huber]

Thanks! I will have to test it out!