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Author Topic: Wacom GD-0912-U vs. Samsng Syncmaster 570P  (Read 15311 times)
Aerendraca
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« Reply #45 on: April 17, 2013, 08:32:54 PM »

Ok, well the first picture of the FPC - What's the pitch of the contacts? If the pitch is bigger than 0.4mm then you could use some 3M 9703 anisotropic tape to join the FPC to a piece of straight FFC of the same pitch. This has been done by someone on the forum but I forget who now, try checking the most recent build logs - wait, found it, it's http://forum.bongofish.co.uk/index.php?topic=2246.15. The tape is sticky both sides and has metal particles through it allowing conduction through the z-axis only, it's simple enough so long as your pitch is ok. You can get the tape 10cm of it for a few pounds on ebay.

The second cable - What does this cable join between? So long as it's not the LVDS cable you could always manually lengthen each wire with some soldering and some shrink tubing, only 25 wires, shouldn't take too long  Cheesy .

And that water stain type blemish looks like an imperfection of the pcb lacquer caused when too much lacquer pools, it wont cause a problem with the working of the circuit.
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bernard
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« Reply #46 on: April 17, 2013, 11:37:45 PM »

there are a few posts talking about extending the FFCs. Recently Chocochan and someone else used a special 3M tape. Which I think was a great thing.
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bernard
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« Reply #47 on: April 17, 2013, 11:41:46 PM »

have you measured the number of pins and the pitch? (I am talking about the first connector which is flat). the pitch is typically 0.5mm total width divided by the number of pins.
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Agerkvist
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« Reply #48 on: April 21, 2013, 02:41:47 PM »

there are a few posts talking about extending the FFCs. Recently Chocochan and someone else used a special 3M tape. Which I think was a great thing.

Hmm yeah I think I vaguely remember coming across that, but it didn't strike me as being something that could be used in my case - I'll read up on that for sure.

And no, I haven't measured the pitch yet, had a busy weekend, so hopefully I'll have time this afternoon.
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Agerkvist
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« Reply #49 on: April 21, 2013, 07:42:02 PM »

So we have 20 pins and a width of 10 mm (well maybe 10,25 mm, but I guess this will count as 10 here) which makes it 0,5 pitch which seems par for the course.

I buy stuff from 3M at work sometimes so I think I'll try giving them a call asking about that tape. All though even if I get some tape, I'll still need some FFC to do the actual extension with - and this FFC would just get taped together with the FPC in one end and connected to the zif on the other?

I honestly don't know what a LVDS cable is or if this is the one so I've uploaded a shot of the entire panel backside:

http://db.tt/bv75bZgY
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bernard
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« Reply #50 on: April 23, 2013, 02:20:23 AM »

For some reason, I cannot access your image.

Ok, found the tape model: 3M9703   3M™ Electrically Conductive Adhesive Transfer Tape 9703  -- I am not sure if it is "certified" to work with 0.5mm but I believe it worked for whoever tried it here. You might have to do some precise alignment, but it seems this is workable with a bit of patience.

Yes, you still need to find an FFC cable, but this is a standard part. Figure out the length you need (think about how the cable needs to be folded). Use a piece of paper cut to the good size to try it out.
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Aerendraca
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« Reply #51 on: April 23, 2013, 02:12:19 PM »

3M 9703 tape is good down to 0.4mm pitch so you should be fine with 0.5mm (see chococans build log for more details).

And from your image it looks like that is the LVDS cable (the cable which joins the controller circuit to the TCON (Timing Control) circuit of the LCD. I notice that the cable is not comprised of twisted pairs or wires, that the overall size of the screen is on the smaller size, and that the wire has a ferrite choke on it; therefore perhaps the reason why there are no twisted pairs is because there is not as data being transmitted due to the reduced pixel count, and that the ferrite choke is enough to suppress and noise. This makes me think that you may get away with manually lengthening these wires by maybe 10cm tops, but you should try to keep each wire the same length. I believe it was Dragon who tried to do this on a larger screen and failed reporting that the screen showed a lot of noise (see Dragontiq - http://forum.bongofish.co.uk/index.php?topic=2052.0).

Quick explanation of twisted pair differential signalling:
Each wire of each twisted pair has an equal and opposite signal send down the line, at the end of the line (at the TCON) the signals are subtracted and any signal which remains is considered to be noise and hence ignored by the TCON leaving only the desired signal to be processed. This system is a very good way of reducing external EMI noise from disrupting the LCD picture.

Like I said, since your screen doesn't have twisted pairs I would think you should be able to get away with a slight extension. Also that plug on this cable looks familiar, think I may have ID'd this for someone else in the last few months, I'm thinking it has a name like something from the sea trident/triton/kracken/...............could be wrong though. If I find the post I'll stick a link here, alternatively whoever it was that was looking for an ID might be able to provide the link or name themselves.
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Agerkvist
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« Reply #52 on: April 23, 2013, 07:19:03 PM »

Wow you guys are awesome. My hat goes off to you both.

You just get a file missing message or something when trying Bernard?  Try refreshing the page and it should work - I just had the same problem when I tried.

Aerendraca that was some reply - I had to read it several time, but now I get it. Well most of it or at least the jist of it.

I'll cut some cardboard sheets and do some testing too see if I absolutely have to extend them or not. My guess is I do, but I also think 10 cm would be enough.

I'll be back when I have moved from "I think" to "I know".
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