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Author Topic: Finally Ready; A Newbie Build for a Newbie Maker - Syntic  (Read 7204 times)
Aerendraca
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« Reply #30 on: November 18, 2015, 10:05:58 AM »

I would say that if you already have the controller for this screen to use the same type of panel. The 15.4" market is fairly small in terms of variety as it was an aspect ratio that did not become popular in the mobile world. If you upped the size to a 15.6" I would look into the possibility of going for something like the LP156WF4 (which was my original choice for the Serenitiq2 before I went retina).
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comfychair
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« Reply #31 on: November 18, 2015, 10:17:37 PM »

Thats what I was thinking

I'm still gonna try to fix it by splicing some wires on the flat ribbon cable at some point

How did the LP156WF4 do in terms of interference/jitters false clicks?

Would you say that a retina display is better in terms of interference?
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comfychair
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« Reply #32 on: November 19, 2015, 12:25:22 AM »

ok so you never got to use the LP156WF4....(I found your post)
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Aerendraca
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« Reply #33 on: November 19, 2015, 07:43:23 AM »

Yes that's correct I never did try it in the end, I spent a lot of time researching and then got frustrated with sellers mis-advertising. Reflecting on it now, the first screen I received would have done just fine in terms of a replacement; I still have the controller for the screen somewhere.
 
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comfychair
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« Reply #34 on: November 20, 2015, 12:03:01 AM »

Are you having any interference issues with the  Serentiq2? - or have you not tested it yet?
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Aerendraca
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« Reply #35 on: November 20, 2015, 08:18:55 AM »

Would you believe I'm 2 years in building this thing and I've not tested it for jitter! However Bumhee34 has done exactly the same build as me with success so I'm not worried, I know I can get it working well.
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comfychair
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« Reply #36 on: November 23, 2015, 11:46:33 PM »

I'll have to look up his build  Smiley

Alright, a quick update

I ordered another LP154WE3 with some bad pixels and salvaged the LEDs and diffuser sheet. My display is now working again! I attached the ground wire to the TCON board and wrapped it individually from the display. As of now, I have no jitters or false clicks and my read height is mostly back to normal (I have to measure) Smiley

But as comicsguy showed us, grounding and shielding are not a panacea, I now have random dropouts.  Undecided It seems to take a moment for the tablet to pickup the pen but if you keep hovering over it, it eventually starts working.


Any ideas? Does this sound familiar?
All I know to do is ground the copper tape surrounding the TCON, lower the display resolution, or start experimenting with powerstrip.

I have not forgotten about the pictures and will be posting soon

Thanks guys
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Aerendraca
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« Reply #37 on: November 24, 2015, 08:01:10 AM »

It could be that the copper tape isn't doing s good job at shielding. Whilst I partially agree that shielding is not the magic cure of jitters for some screens, I do believe that for most it can be, it's all about implementation.

There are some basics which maybe should be noted somewhere;

A Faraday cage should be electrically conductive across the whole surrounding surface. This means than patches of material that make up the cage should have electrically conductive adhesive to complete the circuit.

Copper tape, aluminium tape, and aluminum foil are not great materials for shielding emf at the amplitudes and frequencies we tend to deal with here. This is mostly due to the thickness of the materials; the magnetic part of the electromagnetic interference can permeate the foil/tape allowing induction to still take place. You might try placing a steel ruler between the already wrapped tcon board and the digitizer to see if you can absorb some of the interference; being ferrous the steel should allow the emf to dissipate within. Note the ruler should be earthed.

There should be one path and one path only to ground from each part that requires grounding. More than one path can creates a ground loop and can promote oscillation of the emf making the interference worse.

Lastly and most importantly, shielding emf is not the same as casting a shadow by blocking the path of light. Emf creeps around materials, so generally the idea is to guide it away from the area to be protected. A sorce of emf can be relatively well contained within a Faraday cage because the cage acts to guide the signal around it. A quick note here, a steel cage would be better for the reasons noted above. Also worth noting is that aluminium and copper do not absorb emf at 600-700khz they reflect it, meaning that your cage should be well made without holes where leakage can occur.

That'll do for now, if I think of anymore I'll update this.

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comfychair
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« Reply #38 on: November 25, 2015, 06:56:32 AM »

I could write a book with all the things I'm learning here  Smiley

I'll try to find some metal or a ruler like you suggested and will report back.

I am so close though, the only thing left to remedy is the random dropouts and it will be a perfect build.

The way I see it there are two things that would really help:

1. extending the PFC cables to allow the TCON to be further away from the display
2. Have a steel enclosure custom fabricated. (I am considering using the metal (aluminum?) shielding that came with the display as the metal box.)



I have been all over the internet  trying to find a method to extend a tiny PFC cable. Can anyone out there point me in the right direction?
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Aerendraca
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« Reply #39 on: November 25, 2015, 07:26:04 AM »

I think you need to post some pictures of the fpc cables that you're referring to so we can see what you mean. I suspect that you will not be able to do this as the pitch of the cable is likely to be too fine to do anything with without specialist tools.
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comfychair
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« Reply #40 on: November 25, 2015, 11:48:56 PM »


Here is the panel after I wrapped the TCON board up

* tablet.jpg (85.68 KB. 816x460 - viewed 215 times.)





Here is the wire in question, the one I want to extend is also the one I broke

* cable to be extended.jpg (120.04 KB. 816x460 - viewed 239 times.)


The wire attaches the LEDs and diffuser sheet to the TCON board

* cable and LEDs.jpg (131.32 KB. 816x460 - viewed 225 times.)


* cable and leds 2.jpg (75.79 KB. 816x460 - viewed 221 times.)



I have been looking but I havent found a way to extend these. I hope its possible




This pic shows the earthing wire,

* is this properly earthed.jpg (85.52 KB. 816x460 - viewed 229 times.)

The top wire is screwed to an earthing point on the tcon board, the bottom is soldered to the copper tape. I spliced both wires together and bonded them to the wacom board seen at the beginning of the post.
Will this do?

Has anyone considered earthing that metal plate inside the tablet?


Also The power supply to the controller is making a quick clicking or buzzing noise, that cant be good...

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Aerendraca
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« Reply #41 on: November 26, 2015, 07:39:55 AM »

Ok, I see what you mean now. You might actually be able to extend that wire, you'll need to find an FFC (flexible flat cable) with the same pitch as that part and at a length you need, the only thing you need to make sure is that the ffc you get has the exposed pins at the top on one end and the bottom on the other.

Then you'll need to get hold of some 3M anisotropic 9703 tape; this tape has tiny conductive particles in that only conduct through the thickness of the tape.

The next step is pretty simple, you tape the two ffcs together and squeeze together hard. It might be worth wrapping the bonded ffcs with some other tape by means of securing them.

The earth write you have sounds well implemented so I wouldn't worry about that,n and the plate in the tablet is already grounded within so no need to worry about that either.

The clicking power supply, shoes it only click when it's plugged in to the lvds controller? Or does it click all the time?
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comfychair
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« Reply #42 on: November 27, 2015, 07:00:37 PM »

I may have found the cable i need

http://www.ebay.com/itm/20Pcs-0-5mm-Pitch-9-Pin-AWM-20624-80C-60V-VW-1-Flexible-Flat-Cable-FFC-200mm-/321854744287?hash=item4af009a6df:g:jzwAAOSwLVZV6laD

It is plenty long enough and a D type configuration

the cable width is 5mm

* cable width.jpg (495.65 KB. 1881x1375 - viewed 187 times.)



i cant tell what the pitch is, I dont have a ruler small enough, Im going to assume 0.5mm. thats the most common.

* cable pitch.jpg (292.51 KB. 1428x1296 - viewed 216 times.)



Does everyone agree?

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Aerendraca
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« Reply #43 on: November 27, 2015, 08:11:53 PM »

0.5mm seems likely to me.
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comfychair
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« Reply #44 on: November 27, 2015, 09:16:16 PM »

Has anyone tried lead tape? Golfers and tennis players use it to adjust the weight of their equipment. Thinkit would work?
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