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Trellot

Missing pads on 12-pin controller board connector - Any workarounds?

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Hey guys,

 

Take a look at the following pictures. This board is an Atari 2600 six-switch model and after pulling the 12-pin connector since I suspected a bad connector I found pads missing from some of the pin locations on top and bottom. Any idea if there is a workaround for this problem, or is the board shot at this point?

 

Thanks,

 

Trellot

 

 

post-63859-0-66827900-1529799083_thumb.jpg

post-63859-0-00841100-1529799100_thumb.jpg

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Those will actually work just fine. The board is a single layer board so there aren't any hidden traces within the layers of the PCB. If you look at your pics again more carefully, you will see that the parts where the pads still exist are at the point where they actually meet with the traces on the boards or at least appear to. So while you loose some rigidity of the soldering, you have plenty of other pins still good to go to hold it all in. If you want to make sure, the best thing to do is to grab the schematics for the 6 switchers and simply look at the section for the cart port connector. The pins are numbered and you will want to make sure that you have continuity from where the pin is on the board to the next major component it should connect up with. If you find one that isn't, then you use some thin wire to jumper the missing trace back to the component.

 

I just had to do this very thing with a Maria chip in a 7800 that was sent to me for AV work. It came to me with flickering video at first and after about another 2 hours of burn it, the color blue and green were just gone from the video signal, but only on 7800 games. Found out it was the Maria chip but it also had a broken and missing trace from pin two to where it meets up with the 6502. Used a piece of 30ga kynar to repair the missing trace.

 

I just looked at your pics again, and the pads that are missing are still attached to their traces on the opposite side of the board so they should be okay. The pads that are missing on top have their connections to the traces on the bottom solder side of the board. Shouldn't be any issues.

Edited by -^Cro§Bow^-

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Those will actually work just fine. The board is a single layer board so there aren't any hidden traces within the layers of the PCB. If you look at your pics again more carefully, you will see that the parts where the pads still exist are at the point where they actually meet with the traces on the boards or at least appear to. So while you loose some rigidity of the soldering, you have plenty of other pins still good to go to hold it all in. If you want to make sure, the best thing to do is to grab the schematics for the 6 switchers and simply look at the section for the cart port connector. The pins are numbered and you will want to make sure that you have continuity from where the pin is on the board to the next major component it should connect up with. If you find one that isn't, then you use some thin wire to jumper the missing trace back to the component.

 

I just had to do this very thing with a Maria chip in a 7800 that was sent to me for AV work. It came to me with flickering video at first and after about another 2 hours of burn it, the color blue and green were just gone from the video signal, but only on 7800 games. Found out it was the Maria chip but it also had a broken and missing trace from pin two to where it meets up with the 6502. Used a piece of 30ga kynar to repair the missing trace.

 

I just looked at your pics again, and the pads that are missing are still attached to their traces on the opposite side of the board so they should be okay. The pads that are missing on top have their connections to the traces on the bottom solder side of the board. Shouldn't be any issues.

 

Sorry for my late response/update ... been busy and distracted, etc.! So, after installing the new 12 pin cable I purchased, I'm getting a black screen (did all this months ago!). Of note, I had to remove the 12 pin male header originally on the switch-board and replace it with a 12-pin single socket since the cable I purchased had only straight male ends. Continuity seems to check out. Regarding the chip-side pic above, I'm wondering if I should go back and solder pins 4 and 5 from the chip-side of the board? Note sure if the solder made it to the top in order to connect properly with traces there? ... I'll check on that.

 

~ Trellot

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Good point on that. With a socket in there you can't really tell if solder got to where it was needed. I think I would just solder the ribbon cable directly to this board to make sure, and then perhaps try moving the socket to the other end. I might have even done that myself once or twice now that I think about it.

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It is possible to buy a solder pad repair kit which comes with replacement pads. As Crossbow says, it appears that the pins are all there where it matters. But you can still slip some replacement pads on the bottom side where they're missing in order to provide some anchor points. Otherwise use plenty of flux and use enough solder to go through the hole to the pad on the top side where the header is.

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ChildOfCv,

 

What solder pad repair kit, in my case with this old Atari 2600 issue, would you recommend for me? I've looked for this before and nothing ever seems to be what I think I need lol! Thanks for any suggestions should you have any.

 

~ Trellot

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Hmmm... Well, back in the 70s/80s, my mom used to do rework, and had an entire organizer full of various pads. You could grab one, slip it over the pin, and solder it on. Looks like these days, they've gotten more sophisticated (and expensive):

 

https://www.amazon.com/Circuit-Frame-Plated-Through-Repair/dp/B072XW4P7S/ref=sr_1_37?keywords=circuitmedic&qid=1553338588&s=gateway&sr=8-37

 

The idea is you'd pick out the correct size pad for your pin, and cut off the eyelet with some length of trace to replace what went missing. Of course in your case, all you care about is the pad. But still, it appears that you'll have to spend some money to get those extra anchor points.

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What about using copper tape? I got a roll from Frys back in December and it is conductive on both sides including the sticky side and seems to take heat okay. I wonder if you could get a roll of that, use a hole punch to make the pad itself, and then stick it onto the PCB where the old pad was. Use a needle or other very sharp instrument to get a hole in the middle of the pad for the lead pin to come through. Then try and solder it down. Luckily those pads are fairly decent sized and not the small 1-2mm pitch pads we deal with these days.

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FWIW, I sometimes replace a pad that's lifted with a spiral of component lead. You can glue it down with a dab of UV cured solder resist, since most light will pass through the spiral.

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Posted (edited)

What about using copper tape? I got a roll from Frys back in December and it is conductive on both sides including the sticky side and seems to take heat okay. I wonder if you could get a roll of that, use a hole punch to make the pad itself, and then stick it onto the PCB where the old pad was. Use a needle or other very sharp instrument to get a hole in the middle of the pad for the lead pin to come through. Then try and solder it down. Luckily those pads are fairly decent sized and not the small 1-2mm pitch pads we deal with these days.

Thanks guys for the comments. I've thought using metal tape before, but always worried about it possibly lifting at some point; could be worth a try though.

 

~ Trellot

Edited by Trellot

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Thanks guys for the comments. I've thought using metal tape before, but always worried about it possibly lifting at some point; could be worth a try though.

 

~ Trellot

 

Valid point. I guess my thought was that if it takes solder and holds the lead in well, then that pad isn't really going anywhere afterwards as it would be attached to the lead at that point. And even if it came loose from the PCB, it doesn't matter since you are only wanting it there as an anchor anyway.

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Valid point. I guess my thought was that if it takes solder and holds the lead in well, then that pad isn't really going anywhere afterwards as it would be attached to the lead at that point. And even if it came loose from the PCB, it doesn't matter since you are only wanting it there as an anchor anyway.

That is true regarding the initial anchoring. I think I'll try this then, hopefully this weekend! What would you say about straight metal tape, not copper? I have a roll of that, but can get the copper if that will work better? :)

 

~ Trellot

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Could work, but obviously you need to test it and see how it handles the heat of the iron and solder.

 

I still think you might be better off if you just forgo the connector and solder the wires straight to it. If you want a way to be able to remove the ribbon cable when needed, then think about using pin headers and connectors on the current ribbon cable?

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Also, remember that with a large mass of metal, you will need a bigger/hotter tip to keep the solder melted properly. So if using metal tape, cut into shape first and solder second, to minimize the needed heat and thermal transfer.

 

Hmmm, I wonder if a leather punch might be able to make a hole in the tape small enough to act as a pad?

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Posted (edited)

Another thought...are the pins off the connector long enough that you could could perhaps solder the connector in but not have it sit flush on the PCB? That way you might have more room to get the iron on the pins beneath the connector to ensure solder attaches where it needed to?

 

Another thought, (although this might not work due to the heat needed) would be to attach some cut leads off other components to extend the pins on the connector so you could mount is a bit higher to get the iron in and under it that way? But again with the neat needed for the initial attachment to the pads, you might get it all too hot and the lead just comes loose from the connector pin leads.

Edited by -^Cro§Bow^-

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