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Author Topic: Finally Ready; A Newbie Build for a Newbie Maker - Syntic  (Read 7661 times)
comfychair
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« Reply #15 on: October 30, 2015, 08:10:15 AM »

Good news everyone!

I did not destroy anything. and the false clicks are gone! Grin

However I am now getting random intermittent drop-outs...

I have never gotten these before and are too random and far apart to find any pattern to them.

I am going to reassess the copper tape shielding around the TCON board. Any ideas are welcome.

But we are on the right track, This IS improvement Smiley
 
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comfychair
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« Reply #16 on: October 30, 2015, 09:26:02 PM »

OK with some preliminary tweaking, I think the drop outs were caused by my makeshift copper shielding not being sealed.

I am having an issue with keeping the ground wire affixed to my components. I will try some glue and report back.
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Aerendraca
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« Reply #17 on: October 31, 2015, 12:52:14 PM »

Sounds promising so far. You could try electrically conducting adhesive, it might work ok for this task - regular glue probably won't.

You can also get copper tape with electrically conductive adhesive which should work too (although be wary of copper tape that says it's conductive but doesn't specify what it means, these are usually thermally conductive and wouldn't be any good for this.

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comfychair
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« Reply #18 on: October 31, 2015, 06:05:27 PM »

I do have electrically conductive copper tape backed with electrical tape. Do I need to ground it as well?

Right now I have lost some read height and the signal intermittently drops out completely with the occasional false click - though it is not nearly as bad as before.

Also, is now the time to start playing with Powerstrip?
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Aerendraca
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« Reply #19 on: November 02, 2015, 04:13:07 PM »

You could try grounding the copper tape too, couldn't hurt (as long as the tape is not touching anything it shouldn't be). Do you have some more photo of how you have everything setup? Some shots showing the whole setup would be useful so I can get a picture of how it all looks.

Also, Powerstrip should be considered a very last resort; The likelihood of altering TFT timings reducing jitters is limited, it can make a difference in some cases but in my experience it's a frustration generator and a time eater - you may have little to show for after hours of tinkering with it.
« Last Edit: November 02, 2015, 04:18:02 PM by Aerendraca » Logged
comfychair
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« Reply #20 on: November 02, 2015, 08:56:15 PM »


Here it is so far


* setup.JPG (172.19 KB. 1288x966 - viewed 207 times.)



* setupground.JPG (146.17 KB. 1288x966 - viewed 183 times.)


I have virtually no jitter and it works near the edges too Grin

The only problem is a random false click. It manifests like this:
   
   I hover the pen over the display, then randomly, the cursor starts drawing, making a continuous mark. I can usually make it stop by touching the pen to the surface. (is it a defective pen?)

 

(never mind the white sheet under the TCON, That just some extra copper shielding im trying out)

The ground wire is roughly here, attached to the grounding point/screw hole.


* LP154WE3_TLB1.jpg (99.68 KB. 1000x720 - viewed 183 times.)


I may try to take another wire and solder it to the top of my copper tape enclosure, then splice it into the existing ground wire.


I have read that poorly made power supplies can through off a lot of EMF, (the one I have is from China), is it worth trying another better made one?

and I'll hold off on the powerstrip for now

p.s : Thanks to DaBotz, I got 1 ferrite core around the usb cable of the tablet. I will update when I get more.

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comfychair
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« Reply #21 on: November 02, 2015, 09:00:35 PM »

Also, I have considered extending the TCON board away from the tablet. Is it possible to extend a 4 wire flat ribbon cable?

The TCON board has 3 flat ribbon cables coming out of it. 2 of them are long enough, but the third in the middle is very short. It can be removed from the TCON board safely, but I need to extend it.

It looks like it is the wire that is responsible for powering the LEDs
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Aerendraca
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« Reply #22 on: November 02, 2015, 10:20:21 PM »

Hmm, interesting problem. I guess you could try to duplicate the random click without the screen switched off, that would tell you if it's a dodgy pen (though I suspect the pens fine). Everything looks good though so far.

If you put a blob of solder flux paste on the copper tape it would take the solder much easier and should create a nice strong join.

Joining the ground by splicing should be alright so long as you don't create ground loops, there should be one path to ground from each part being grounded otherwise there is a possibility that the electromagnetic interference can oscillate and make matters worse.

Poorly made power supplies can give off a lot of EMI that's true, you could try a different supply but I suspect with the success you've seen so far, a new power supply wouldn't make too much of a difference. If the power supply has an FFC number on it you can look up the EMI test and see if it's the real deal (there's a link somewhere on the forum, I can hunt it down if need be).

Moving the TCON would be ideal, however I'm sorry to say that this is but a dream. Sadly the TCON is permanently adhered to the glass and non-extendable. Out of curiosity what screen are you using? I'm a little confused by
Quote
The TCON board has 3 flat ribbon cables coming out of it. 2 of them are long enough, but the third in the middle is very short. It can be removed from the TCON board safely, but I need to extend it.

Do you mean the LVDS controller or am I grabbing the wrong end of the stick?
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comfychair
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« Reply #23 on: November 03, 2015, 12:30:24 AM »

A lot of good information  Grin

I will try grounding my makeshift faraday cage and let you know


About the TCON board: I should be more clear

There are three flat ribbon cables coming out of the bottom of the display and going into the TCON board.
2 of these cables do come out of the glass (like you mentioned) and I suspect are responsible for the video signal going to the screen itself.

the third wire in the middle is the smallest and is attached to the LEDs on a white diffusion sheet. It is attached to the TCON board by a connector. (I dont know what these connectors are called, but you can open a lever and release the wire) This is the wire I would like to extend.
I would love to post pictures, But already have everything sealed. I would have to tear away the copper tape and dont have enough to re-seal.


I have a suspicion that my copper tape is coming looses from the screen. I have reinforced it and will continue testing after my shift.

Thanks all and thanks Aerendraca
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comfychair
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« Reply #24 on: November 06, 2015, 05:32:08 AM »

ok I've got some promising results!

I bonded the copper tape, display and tablet and I am seeing better results but still getting the false clicks.

I got to thinking, I am only surrounding three sides of the TCON board. So I tried to completely surround the board with more tape. I didn't do a great job; I left a couple of gaps but I could tell a BIG difference.

ALL false clicks stopped until about 4 inches from the bottom. If I can manage to get complete coverage and ground I might just get it. I have to order more copper tape to continue and I'll post more pictures when it comes in.
A question in the mean time: Do those anti-static bags that motherboards come in protect against EMF?
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XDjackieXD
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« Reply #25 on: November 06, 2015, 03:31:27 PM »

I don't think that the anti static bags stop EMF...
You could use aluminium foil though (but be careful to not short anything...)
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Aerendraca
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« Reply #26 on: November 07, 2015, 12:14:01 AM »

I have to agree with XDjackieXD, esd bags are no good for Emi on account of them being made from relatively low conducting material which is very thin
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thatcomicsguy
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« Reply #27 on: November 07, 2015, 10:23:23 AM »

There should be a notice somewhere.

Shielding doesn't work.  You can shield everything right up to the screen, but the screen itself is also a transmitter, and you can't shield the screen (because that would defeat the purpose of having a screen.)

The signal being output by the video controller has to be such that it doesn't interfere with the stylus and digitizer antenna system.  It's that simple.

How do I know this?  Well, aside from having tried every shielding strategy in the book, and from the countless failed attempts of every body else on this board, I actually tried the following which proves that shielding is a pipe dream:

I pulled the LCD and chipset components from a Cintiq 21UX and replaced them with the same components from an otherwise identical 21" monitor.  Everything was physically the same down to every screw and every tab and slot.  The screen dropped right into the Cintiq chassis and fit like a glove.

I did this because the original screen had a bruise on it where somebody had presumably elbowed or dropped some heavy object on the Cintiq, and I thought I could fix it by swapping out the LCD component from a cheap-ass used monitor from eBay.

Everything worked, I powered it up and my Cintiq was bright and beautiful and...

Had a terrible case of the jitters.  I swapped the original screen back in and the jitters vanished.  So now I just use it with a bruise.

-The shielding was identical between the two components, (and I should add that there is barely any to begin with).  But one screen caused problems with the digitizer and the other did not.  So I know it had nothing to do with the shielding and everything to do with the LCD component itself.

In short, if your LCD isn't designed to run at a compatible frequency which doesn't cause problems with the stylus or digitizer antenna array, you're going to have an incurable case of the jitters.

People who claim to have built DIY Cintiqs with no interference issues are experiencing one of two things...

1. They lucked out and got screens which were compatible with their chosen digitizer layer.

2. They have interference problems but have learned to live with them or work around them.

Typically, moderate jitter/false click problems only happen around the extreme edge/s where the LCD is connected to the driver chipset, so one way around the problem is just to program your board to leave an inch of dead space along the affected edge/s of the screen.
« Last Edit: November 07, 2015, 10:35:07 AM by thatcomicsguy » Logged
comfychair
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« Reply #28 on: November 14, 2015, 04:35:53 AM »

I was afraid of that and you are right, I have had hit and miss results with the shielding. Is there any way of fine tuning the video controller or LCD? (or is this what Powerstrip does?)
My primary problem was false clicks, but I assume that false clicks and jitters are symptoms of the same problem

I did re-wrap my TCON board and covered the leaks and I have to say all my false clicks and jitters are gone....except for the bottom two inches of the screen.

If only there was a way to extend those little flat ribbon cables....

There isnt anything I can do right now other than attaching a ground wire to my copper shielding and seal more leaks. Other than that, I have to find another display :/

but thatcomicsguy brings up another good point, I have looked over the successful builds logs and its hard to tell who is using a screen that they have accepted as flawed or one that truly has no issues. Ill have to keep reading. I am open to any recommendations.

As stated above, I have a PTK-840 intuous4 large
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comfychair
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« Reply #29 on: November 18, 2015, 01:21:25 AM »

Bad news, I broke the ribbon cable that connected the LED to the TCON board  Embarrassed

I'll try to fix it but I'm not opposed to getting another panel. I'm still searching the forum for a recommendation from a successful build.

Any thoughts?
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