Broken pin on IC?

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Ed Oscuro
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Broken pin on IC?

Post by Ed Oscuro »

I noticed at least one, possibly two, of the pins connecting to an IC on the Heated Barrel I just got is hanging loose. The chip is a surface-mounted quad flat package, the most densely pinned chip on the board, a SEI300 / TC25SC900AF. The chip is square, connected to the board on all four sides, and the broken pin is to the very right of a group of three pins that pass under the board, and are marked 184 at the point where their traces surface on the top of the PCB again.

When I first hooked the board into my SG the other day, the monitors (fed via XRGB-2) would continually try to sync. Whenever I could see a picture (for only a few frames at a time) the colors looked right and there was no corruption. I could see the colorful Heated Barrel logo for instance.

So this is a pretty fiddly thing and looks like I'd need at least a low-power loupe to even see what's going on clearly. Is this the sort of thing I have a chance of getting serviced locally, or should I just return the thing and try again?
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undamned
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Re: Broken pin on IC?

Post by undamned »

So, the pins are actually broken off of the chip itself or are the pins intact and they have come free from the solder pads on the PCB?
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Ed Oscuro
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Re: Broken pin on IC?

Post by Ed Oscuro »

It's broken off relatively close to the chip itself. The pin itself is flexible like a trace might be; very thin. I see the pin to the right of the broken-off one seems to run straight from the chip to the pad without taking the usual downward course, so it could be stretched out or broken as well.
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undamned
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Re: Broken pin on IC?

Post by undamned »

That's rough when the pins are small. If you have the ability to take a close up quality photo I might have some suggestions for you...
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Re: Broken pin on IC?

Post by Ed Oscuro »

Dan suggested I hit up Channelmaniac on Neo-Geo.com; I'll take a picture soon as well, hang around...
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IronGiant
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Re: Broken pin on IC?

Post by IronGiant »

If there's enough of a stub remaining for the broken off pins then it should be possible to solder some wirewrap wire from the stub to the pad on the board. I've done this quite a few times - it's fiddly but possible.

If there's not enough of a stub left then the only option (short of replacing the whole chip) is to very carefully (using a Dremel) grind down the IC packaging just above the broken off stub(s) and then solder wire from the then exposed stub(s) to the PCB pad(s). Again, I've done this a few times with good results.

In a nutshell, all is not lost. :)
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Ed Oscuro
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Re: Broken pin on IC?

Post by Ed Oscuro »

43 MB worth of pictures, no cropping done so you can get a slightly better idea of the location. The first couple pictures are off-center to give some idea of the location of the thing.

http://www.megaupload.com/?d=WSZBVLU7

Edit: I forgot to mention that the tiny wire you see in the first couple of pictures has "gone away" after fiddling with it a bit. You can see how things sit now in the last picture at least. With or without that wire in place, the game runs the same way, i.e. won't sync properly but when I occasionally catch glimpses of the screen it looks correct. Sound is accurate and it sounds like the game is playing correctly.

(I need a dedicated macro lens like the MP-E 65...but this $20 lens did good enough.)
Last edited by Ed Oscuro on Sat May 01, 2010 11:58 am, edited 1 time in total.
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IronGiant
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Re: Broken pin on IC?

Post by IronGiant »

Looks like it should be easy enough to repair if you're good at soldering, have steady hands and an illuminated magnifier. :)

The pad which doesn't have a track apparently emanating from it either has a track running UNDER the chip or simply isn't supposed to go anywhere - either way the pin should be properly connected to the pad and the short to the adjacent pin removed. Of course, the pad itself has also been lifted from the PCB, so you'll need to be sure that if the track DOES go under the chip that you don't break off the pad from the track when you straighten the pad ............

How's your soldering? :)
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Ed Oscuro
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Re: Broken pin on IC?

Post by Ed Oscuro »

Someday I'll have to teach myself soldering but I have no equipment to do it with, unfortunately. I have a couple other boards that could have a looking-over as well so I might try to get these all done at the same time.
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IronGiant
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Re: Broken pin on IC?

Post by IronGiant »

That sounds like the best idea.

Where are you based? UK? US? Europe? Outer Mongolia? Antarctica ............ ? ;)
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Re: Broken pin on IC?

Post by Ed Oscuro »

Across the pond from ya, in the ɐɔıɹǝɯɐ ɟo sǝʇɐʇs pǝʇıun

MI to be precise.

I know what you're thinking but that's probably not a good idea for multiple reasons. Going to keep it in CONUSA if at all possible, but I hear good things about your work so I'm sad that it's not a realistic option for me.
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Re: Broken pin on IC?

Post by IronGiant »

Not a problem, just needed to know your location so I could suggest a suitable repairer. As you're in the US then I would highly recommend Channelmaniac. :D
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davidgreem
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Re: Broken pin on IC?

Post by davidgreem »

sorry ones the pin is broken IC will not work properly.Now IC is of no use of any kind so simply replace it with new one no option other than that.
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Re: Broken pin on IC?

Post by Ed Oscuro »

davidgreem wrote:sorry ones the pin is broken IC will not work properly.Now IC is of no use of any kind so simply replace it with new one no option other than that.
what the fucking fuck
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