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Author Topic: Joining high-pitch FFCs : Does DIY Beamer still exist? An alternative...  (Read 8665 times)
Chocochan
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« on: January 09, 2013, 11:21:35 AM »

I'm working on a new build that would actually work this time (I hope) if only I could extend the 45 pin FFC my LCD panel has. I've sent 3 emails to DIY Beamer asking them if they could build a custom extender board for me or even if the 50 pin one they have on their website would work with no inference from the unused pins, but NOTHING. It's really annoying because what they sell would be exactly what I need. I've attempted a 30 pin ZIF connector breakout board before and that was bad enough, I doubt I'd be able to solder TWO 45 pin ones without going insane! Plus the fact they those parts seem stupidly expensive in the UK.

Do you think a 50 pin one will be OK or is there somewhere else I could try?
« Last Edit: February 02, 2013, 03:53:08 AM by bernard » Logged
bernard
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« Reply #1 on: January 09, 2013, 03:00:36 PM »

Hey Chocochan! (SW)  Howdy!

DIY Beamer has a long history of not being responsive for weeks and then suddenly being "back". I have no idea what is happening, probably a one guy-shop. Each time it occurs, we think it is down. Sorry about that, but there is nothing I can do and they are about the only one building those "parts".

Soldering connectors back-to-back is indeed not that easy -- you would need a lot of flux (which greatly helps avoiding bridges). Someone in the forum did a clever thing about soldering this (can't remember who). 

What price are we talking about for the parts?
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Chocochan
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« Reply #2 on: January 09, 2013, 05:21:42 PM »

Well, I haven't actually found 45 pin ZIF connectors yet... When I first needed 30 pin ones, there were places sell them for around £6 each (please note this was eBay, as for some reason they are hard to find in the UK). If you buy them from China you can get 5 for a couple of pounds! I'm using a Mimo USB monitor this time for my build as a previous idea I had went "belly up" despite me having the pinouts (I was making a breakout board for a 30 pin LCD panel and even after designing, etching and soldering the board all I could get was a grey screen with a black line and the LED backlight working, there were no bridges in my soldering either).

The Mimo monitor LCD has one of those horrible flat orange FFC cables connected to the PCB. If it was just a ZIF connector it would've been so easy. I remember another user had a build using a Mimo monitor and his one has a different LCD so all he had to do was just get a longer FFC.  I'm sure it's 45 pins (but my eyes were going blurry trying to count them). It's the last part I need to get to test the LCD over the digitiser board. I've removed some of the metal on the back and stripped the tablet already (I'll save which brand I'm using as a surprise!).

I'm also waiting for a couple of mini USB extension cables. I'm going to solder one to each PCB and attach the female ends to the casing so that the cables can be removed for travel/storage. I'm confident about this build, but the worry is if jitter is present which I can't test because of the bloody FFC!  Angry
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Chocochan
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« Reply #3 on: January 10, 2013, 07:45:45 PM »

Sooooo...

Does anyone know if the extra unused pins on a ZIF connector could cause any problems? I'm tempted to try a 50 pin FFC extender board if anyone has one to sell? I don't think I want to try my luck with DIY Beamer in case they don't actually ship the order...
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Aerendraca
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« Reply #4 on: January 11, 2013, 08:42:49 AM »

Hi Chocochan,

I can't imagine you would experience any problems using a larger ziff connector than required, at least I can't think of a good reason why you would so long as the pinouts match.

As an alternative though, you might be able to use some 3M 9703 Anisotropic tape (conductive only in z-axis) to join another piece of FFC ribbon to make your own extension, I believe this tape can join FFC ribbon down to a pitch of 0.4mm. Not tried it myself but it's a solution that 3M themselves suggest on their site. I've seen small pieces on ebay for a few £ so not too expensive either.

Can you not just buy a longer 45pin FFC cable? Can't imagine that'd be too expensive. Actually I think I might have done this before some time ago when I build a projector with the help of LumenLab (which I'm not sure are still active), I'll have a think about where I might have got it from. You'll need to know the pitch of the ribbon though (which is likely to be 0.5mm I would think).

Maybe something like:
http://www.ebay.com/itm/45-Pins-POWER-RIBBON-FFC-CABLE-AWM-20624-80C-60V-VW-1-/271029503898

or
http://www.ebay.co.uk/itm/AWM-20798-RIBBON-FLEX-CABLE-0-50-mm-pitch-45-PIN-800mm-45PIN-80cm-/221075277566?pt=US_Audio_Cables_Adapters&hash=item33791d06fe (should be long enough)
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bernard
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« Reply #5 on: January 11, 2013, 09:02:54 AM »

Typically the problem is that the FFC to extend is not an actual FFC. It is a thin flexible PCB that has an special shape looking like an FFC cable. In other words, there is no cable!  So there is only one connector on one side!   

Your anisotropic tape is cool! Never heard of that! I assume you need to align it carefully so it does not create bridges, right?  0.4mm is quite close to 0.5mm !
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Aerendraca
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« Reply #6 on: January 11, 2013, 11:23:33 AM »

Well actually so long as you kept the tape perpendicular to the FFC traces you wouldn't need to worry about lining the tape horizontally since there shouldn't be any overlap, see below:


* 0.4mm pitch vs 0.5mm pitch.png (6.21 KB. 645x162 - viewed 381 times.)

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Chocochan
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« Reply #7 on: January 11, 2013, 06:57:36 PM »

Hey Aerendraca,

Bernard is right, this wretched cable is one of those thin PCB like things. Here's a couple of quick pics (Just click "next" to see a close up of the pins):

http://public.fotki.com/Chocochan/desktop/sany0043.html

The anisotropic tape sounds really useful and I found a 100mm piece for just £2.40! However, I still have the problem of finding a 45 pin 0.5mm pitch FFC cable in the UK. I could order it from China, but that's a long wait (I'm still waiting for those mini USB extensions). They're so cheap in China, but really expensive for what they are here (IF you can find them)! The good thing though is that it's just ONE cable to extend. With some LCDs you have to extend the small FFC that powers the backlight too (which was the main issue I had a long time ago with the iPad 1 LCD panel...

I think I'll try the tape and see. It would be a cheaper faster alternative to DIY Beamer...

P.S: How do you attach images to posts? I don't know how. I tried the insert image button, but copying and pasting the link from Fotki doesn't work...
« Last Edit: January 11, 2013, 08:49:34 PM by Chocochan » Logged
Aerendraca
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« Reply #8 on: January 12, 2013, 09:10:07 AM »

I see, how long does the extension need to be?

Underneath the text box there's a link that says 'Additional Options', click that and there's an opption to attatch an image.
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Aerendraca
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« Reply #9 on: January 12, 2013, 10:59:18 AM »

Oh and I found http://www.ebay.co.uk/itm/MULTICOMP-FFC0-50A45-0202L4-RIBBON-CABLE-FLAT-0-5MM-45-WAY-/260963866026?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item3cc2a895aa which looks about right to me.
Only thing is you might want to contact the seller to find out how long it is as it doesn't seem to mention that.
« Last Edit: January 12, 2013, 11:02:29 AM by Aerendraca » Logged
Chocochan
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« Reply #10 on: January 12, 2013, 11:54:14 AM »

Oh and I found http://www.ebay.co.uk/itm/MULTICOMP-FFC0-50A45-0202L4-RIBBON-CABLE-FLAT-0-5MM-45-WAY-/260963866026?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item3cc2a895aa which looks about right to me.
Only thing is you might want to contact the seller to find out how long it is as it doesn't seem to mention that.

Yeah, I found that last night and made an offer. If I do go ahead and get one to use with the anisotropic tape, I would need to alter it by stripping one end reversed (having one side with the silver contacts facing upwards and the other downwards). This is to make sure that pin 1 always remains on the same side since the cable is inserted into the ZIF connector facing down. I learnt this from experience... Not really sure what length I'd need yet, but if it's anything like the image, it should be long enough since I'll be folding the flexible PCB out. I'd say anything over 100mm (10cm) would be fine.

Thanks for the tip about attaching images, should help when I start my build log! Oh yeah, I saw this video when looking for the tape. It shows it being used to fix an iPod and how it works. I think it would be very useful for many builds:

http://www.youtube.com/watch?feature=player_embedded&v=E49tvZ8G3VA
« Last Edit: January 12, 2013, 06:15:48 PM by Chocochan » Logged
Aerendraca
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« Reply #11 on: January 12, 2013, 02:03:40 PM »

I was thinking about using this tape myself to see if I can fix my Samsung Syncmaster 214T screen, where a couple of ribbons have come away from the glass. Think the pitch might be too large on the tape to do this though, but I intend to use a microscope to properly measure the pitch later this week.
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Chocochan
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« Reply #12 on: January 12, 2013, 06:15:29 PM »

Hmmm...

I was thinking about what you said and about pitch. I think it just means that's the finest that can still support a signal? I found this PDF about the tape here:

http://multimedia.3m.com/mws/mediawebserver?66666UuZjcFSLXTtnxfVMxz6EVuQEcuZgVs6EVs6E666666--

I've just asked the seller question about the tape anyway, but from the video I linked, I think it should be suitable for your purpose. Do you think your Samsung's pitch is LESS than 0.4mm?! I know smaller exists, I just haven't seen it myself yet! If it's larger it shouldn't matter. For me, as long as I line up the cable's pins with the extension's ones (which is soon on its way), I should be fine as they're both the same pitch and count.
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Aerendraca
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« Reply #13 on: January 12, 2013, 09:11:23 PM »

Pretty sure the pitch on the Samsung is smaller than 0.4mm which is why i don't think the 3M 9703 tape will work. I know that they do other tapes but the price seems to escalate exponentially as the pitch gets smaller, at one stage I found someone selling a finer pitch 3M tape for £300 per meter! Could buy the screen several times over for that.

The 9703 tape will be perfect for you purposes I have no doubt.
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bernard
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« Reply #14 on: January 13, 2013, 12:23:03 AM »

One thing to watch out about FFC cable -- there are two variants:  one of them "reverses" the signal. That's because sometimes the metal is not exposed on the same side of the cable. It is like looking at yourself in the mirror:  the right hands become the left hand. Make sure you pick the good one for your application.
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