What does the screen calibration app actually do?

[Guest Graham Macleod]

A bodged repair (story below) was rescued by the screen calibration utility from this thread:

A Vega which was unusable because of completely crazy screen behaviour, multiple presses, wrong presses etc, calmed down and could be used again.

How come? What, exactly, does the utility do? I'm puzzled because it insists that you don't touch the screen while it works its magic. That's unlike any calibration that I've ever seen.

Could it be that it somehow reads and compensates for background electrical noise in the machine? Is electrical noise a problem for touchscreen sensors, and if so, how can it be minimised?

I ask because the touchscreen is still erratic. Whether it can be used depends on how and where I hold it. It may be that there is something I can do to screen the sensor from other bits of circuitry and noise.

I don't really know what I'm doing though.

[Guest Graham Macleod]

---------- Longer Story --- to explain.

A couple of weeks ago my Vega's LCD cracked. Vega and Motorcycle Luggage not a great combination. I scanned the forum and decided to try to repair it. I got a screen from these guys http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=160620729572 and set to it.

To cut a long story short, I got it working, but it's a horrible bodge. The new screen is a different size and has the connector in a different place, so I had to remove a lot of the inner structural elements of the vega and throw them away. The Vega is now held together with duct tape inside (but you wouldn't know).

The screen is better though :-)

On first boot the machine was completely unusable, the touchscreen was registering touches pretty much anywhere but where I was touching. It was a disaster and I assumed that the touchscreen sensor had been damaged in the same accident (which is quite possible).

Finally I found the calibration app and was able to get it running. The difference was amazing. My Vega was back, usable, I could type, swipe, everything. So happy!

It's just not quite there. In particular, if I hold the Vega on the left hand side at the bottom, the touches are erratic. If I hold it in the middle it's fine. I am thinking it's an electrical noise issue and that I need to restore some of the screening to the motherboard.

I love this thing and I want to fix it properly.

[Guest richardmlea]

Doh!uble post

Edited August 26, 2011 by richardmlea

[Guest richardmlea]

Hi Graham, good work.

The shielding has to be there for a reason so if you have moved things around inside you may need to add more shielding to compensate.

When you say "the screen is better" what do you mean?

Is the screan better quality than the original? How is the viewing angle. Did you take any pictures of your work and if not any chance of a few?

Cheers

Richard

[Guest Graham Macleod]

Yes, I'm wondering how I can make some shielding - I'm going to need something like insulated tinfoil. There's not much space and the original metal innards are gone.

The replacement screen is better. Not a lot better from the raw viewing angle perspective, quality still falls off dramatically if you tilt the screen. However on my old Vega it really wasn't possible to view from any angle without getting greying on dark areas at the corners. This meant that watching a video, for example, the 'true' contrast area didn't fill the screen, it being a wide band arced up in the centre.

That's no longer the case. If I view the screen full on there's now no greying at all. Which is nice. I wouldn't recommend it for a working Vega though.

I'll try and get some pictures, but unfortunately I've thrown away all the original components (I was on holiday when it happened) so they may not be that informative.