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archeocomp

1mm FFC Keyboard Cable and Adapters

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Hi. OSH Park uses rather rare suffix for board outline. Renaming adapter-kbdv2.GML to adapter-kbdv2.GKO should do the trick. All other suffixes in the zip are identical.

https://docs.oshpark.com/troubleshooting/naming-pattern/

 

Will you choose "flex" the super thin board? Otherwise the standard 2oz boards OSH Park 0.8mm could be too thick. (PCBWay  0.6mm is what I used)

Edited by archeocomp

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Super! Will do.

 

And yes, I was planning to order the thinner flex material. At first I was concerned about soldering onto it, but I'm going to have to do for the motherboard side anyway. I'm sure if I can do one side, I'll be able to do the other.

 

Thank you!

 

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OK, the PCBs are ordered. I should be in for about $60 by the time I get my keyboard repaired, but you don't come across an ALPS Type 1 Keyboard just every other day. One final question @archeocomp, did you just use a standard 0.100" (2.54mm) pin header? I just wanted to double-check on the spacing, in case I need to pick some up.

 

Edited by bfollowell

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On 9/4/2021 at 3:30 AM, archeocomp said:

Yes, standard

Well, I looked at my header pins, and there's definitely no way that there's room between the top of the keyboard PCB and the housing. Maybe just the pins, but not the plastic. I'm going to have to tinker a bit, but I'll get it, one way or another.

 

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Definitely only the pins. I glued the thin PCB on top of keyboard PCB and used header pins only to make soldering an easy task. Afterwards the plastic and other side must be snapped off. Only thing that remains of it are the pin cuts buried in solder blobs connecting the two PCBs.

You could as well use 16 short wires, approx 2-3mm each. But that would take 10x the time and 10x the effort. Sacrificing pin header is so much easier.

Edited by archeocomp

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2 hours ago, archeocomp said:

Definitely only the pins. I glued the thin PCB on top of keyboard PCB and used header pins only to make soldering an easy task. Afterwards the plastic and other side must be snapped off. Only thing that remains of it are the pin cuts buried in solder blobs connecting the two PCBs.

You could as well use 16 short wires, approx 2-3mm each. But that would take 10x the time and 10x the effort. Sacrificing pin header is so much easier.

 

Exactly what I was thinking of doing. Thank you for confirming. This will be my first attempt at any SMD soldering as well, so I plan to take my time. I have three of each board coming because that was the minimum order, but I don't want to waste them. I'll probably desolder and remove the old ribbon cable in the next day or two and then it's just waiting for the PCBs to arrive.

 

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I got my connectors in from Newark today. Man! Are these things ever tiny!

 

I've never done any SMD soldering work, and after seeing how small these things are, I have to admit that I'm a little intimidated. I'll definitely be using my magnifying goggles and I'll have to make certain I'm not caffeinated up before I start. Slow and steady, very patient. I'm also glad I bought enough to do a couple of these. Since I had to purchase three each of the two PCBs, and I figured I may mess up on something, I made certain to buy enough cables and connectors to do it at least twice, just in case.

 

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Not ideal doing first SMD ever on flex PCB. But it is not so hard. Use lot (really lot) of flux, very little solder, big iron tip (not too hot, clean). Just gently touch edge of the pins and wait 2s, solder will flow all the way down. No scrubbing or moving of the tip over pins is needed.

 

Do test all connections before installing in Atari. I had to rework it few times, till all the pins were connected on both sides.

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15 hours ago, archeocomp said:

Not ideal doing first SMD ever on flex PCB. But it is not so hard. Use lot (really lot) of flux, very little solder, big iron tip (not too hot, clean). Just gently touch edge of the pins and wait 2s, solder will flow all the way down. No scrubbing or moving of the tip over pins is needed.

 

Do test all connections before installing in Atari. I had to rework it few times, till all the pins were connected on both sides.

 

Would it maybe be better to use solder paste and a hot air rework station at lower airflow and heat, say 450 deg F or so?

 

Edited by bfollowell

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@bfollowell Look up drag soldering videos on youtube, the key here is high quality flux, don't skimp.  Alignment is also key, make sure the contacts are perfectly aligned, and it will go smoothly.  I usually will put solder on only one contact, then move the piece to be soldered onto that pad, while holding the iron on that pad.  Reposition if necessary, until you get the alignment nailed, then you drag solder from the opposite side.

 

For hand soldering, this is much easier than using paste and a heat gun, which can definitely warp a flex circuit.  In fact unless you have a stencil and a reflow oven, for the most part drag soldering is the most effective and easiest in my experience.

Edited by wildstar87

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4 hours ago, wildstar87 said:

@bfollowell Look up drag soldering videos on youtube, the key here is high quality flux, don't skimp.  Alignment is also key, make sure the contacts are perfectly aligned, and it will go smoothly.  I usually will put solder on only one contact, then move the piece to be soldered onto that pad, while holding the iron on that pad.  Reposition if necessary, until you get the alignment nailed, then you drag solder from the opposite side.

 

For hand soldering, this is much easier than using paste and a heat gun, which can definitely warp a flex circuit.  In fact unless you have a stencil and a reflow oven, for the most part drag soldering is the most effective and easiest in my experience.

 

I'll look into that method. Luckily, I have three of each PCB coming!

 

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Well, I've received my cables and connectors and, as of today, I finally received my boards from OSH Park. The boards and the connectors are small, no doubt, but not horribly so. Honestly, they don't look too bad. Assuming I take my time with them, and tack the connectors down by soldering one pin on each end, then taking my time to move across, I really don't thing it'll be too much of a problem. I think the key will be to solder a pin or two, the back-off for a couple of minutes so that heat doesn't buildup too much on those flex boards. I'll just have to take my time and see how it goes. I look forward to giving it a go this weekend.

 

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The weather is getting more mild, so I thought I'd go out into my garage workshop and work on putting this cable assembly together to get my keyboard going again. Holy Guacamole! Am I ever shaky and trembly!! I knew I was getting more so for fine work as I'd gotten older, but I had no idea until I saw it under a soldering microscope! I know everything under there is magnified, but sheesh!

 

Anyway, I bought an Andonstar AD407 soldering microscope and that helped much more than my magnifying goggles. Also, this was my first try at SMD. I didn't try drag soldering or any of the techniques I'd seen on Youtube. I just tacked the connector down with one pin on each end, then went slowly and methodically across, pin by pin. I had to fix a couple of solder bridges, but other than that, I don't think I did too bad. I checked continuity from the connector to the end of the molex cable, and everything looks good, with no shorts except for pins 18 & 19 and 20 & 21, which seem to be shorted by the board, and not my shaky hands.

 

Soldering the keyboard PCB to the keyboard shouldn't be too bad. Those are much larger, more normal soldering and I shouldn't mess those up too bad, shaky hands or not. I just need to get the motherboard side connector board soldered and the old keyboard connector desoldered and the new keyboard connector soldered in its place and I'll be ready to try it out. I'm not sure I'm up for any more today though. I'm not sure my old nerves could take the stress. I think I'll wait and get the motherboard connector one day during the week. I should have it going again soon though.

 

I bought a 12" molex cable too, so I shouldn't have any trouble having plenty of slack to pull the keyboard and motherboard apart in the future, regardless of whether or not I actually disconnect the cable.

 

 

2021_1017_142936_217.thumb.JPG.f0e47f469306eb3bf0872057c8e4ee0d.JPG

Edited by bfollowell
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Well, I did go ahead this evening and soldered up the motherboard-side connector PCB. It went well. I went ahead and removed the old ribbon cable from the keyboard PCB. Some the old traces on the keyboard PCB are not quite as resilient as the traces on the main motherboard. Between desoldering the ribbon cable and soldering the header pins in for the new flex-PCB, several traces have lifted, so I'm going to have to cut some jumpers and do some patching later. I'm still determined to get this keyboard back in good operating shape though.

 

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So, pads 1, 10, 12, 13, 14, 15 & 19 have all at least partially lifted. Seeing as there is no through-hole barrel and these were just surface pads, I really shouldn't be so surprised. Still, I was really surprised by the sheer number of pads that lifted. I haven't had this much trouble in all of the time I've been repairing boards. Looking at pad 19, the one that lifted completely off the board, as near as I can tell, it isn't even connected to anything, so I'm really not sure what that one's even for.

 

Do any of the rest of you see anything I don't? Is pad 19 connected to anything?


 

Keyboard.thumb.jpg.251e6c3c0f9a311d28a54c7c3905e2ef.jpg

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Pad 19 is +5V Volt, it is not needed for anything on your keyboard IMHO. You keyboard PCB type is different from mine. I also had a jumper wire in that area that I had to move to opposite side of the board, as it was in the way of new connector board coming there. My photos show it.


Btw I did not lift a single pad. Must have had better board definitely.


On eBay in US they sell JB Weld HighHeat Epoxy, rated to +500F(+260C), that might by useful for fixing those lifted pads.

 

Edited by archeocomp

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