Author Topic: DigiX SMOKE! (Dead R.I.P.)  (Read 4993 times)

Solice

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Re: DigiX SMOKE! (Dead R.I.P.)
« Reply #15 on: January 29, 2017, 10:48:48 am »
I looked around, and it appears that I don't have any quad flat pack IC breakout boards left to demonstrate this on, but I do have some SOIC's, so I'll be demonstrating this technique on an SOIC16 74HC595D 8-bit shift register.  The pin pitch is different from the QFP you're going to be doing this on, but it works just the same thanks to capillary action of solder.  I don't have a camera rig for this, so there are no action shots, just post-step shots.





Put a dab of solder on pads on opposite sides.  We'll use this to tack the part down.


Place the part on top of the pads, holding them with tweezers.  While the part is held in place, press the iron onto one of the pins that has solder under it.  Don't worry about bridging; that will be fixed later.  Once one pin is tacked down and straight enough, do any others.  Keep in mind that while the first one is being worked on, you can still adjust position if necessary.  It becomes difficult after that.


Now, ready the barf bag.  One side at a time, dump solder on top of the pins, forming bridges across them.


It's important to do all sides before we do anything else, just to make sure the pins don't drift during cleanup.


This is the guy I used for clean up.  It's possibly the cheapest, most readily available solder pump money can buy, but it gets the job done.  Just heat the pins and suck up the solder as necessary.


You'll notice that sucking up solder will only remove solder that has not adhered to metal.  Anything being repelled by the solder mask or free flowing will not stick around.


...and we're done.  Hooray!


Looking at the DigiX, you have considerably less space to work with, but this technique should still work.  The part you'll need to look out for is the initial alignment of the pins and maybe clearance for your iron near the 6-pin ISP header.  I hope this helps!

exeng

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Re: DigiX SMOKE! (Dead R.I.P.)
« Reply #16 on: January 29, 2017, 12:47:11 pm »
Solice, Thank you big time for the slideshow. I'm still holding off until I can find a junk board to practice on with the old part. I figure I've got 4 sides so I could 4 methods to see which works the best. Yours and solder paste are high on the list.

Thanks,
exeng

PeterF

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Re: DigiX SMOKE! (Dead R.I.P.)
« Reply #17 on: January 29, 2017, 10:04:11 pm »
A big thank you from me also Solice... that looks like a very neat way to do some of the nastier pitch SMD stuff... make it looks easy! :-D

exeng

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Re: DigiX SMOKE! (Yes Mostly Dead R.I.P.)
« Reply #18 on: January 31, 2017, 08:01:06 pm »
Well, I gave my best shot. Got the MCU down with the exception of PB6 (pin 96) and PB7 (pin 97)... who needs those when you have a plethora of digital pins. Busted one off and lifted the pad on the other while (whilst for Pete) trying to encourage one back on it's pad.

Powers up but DigiX not recognized. PWR led on and pin 13 LED stays on. So at this point I'm calling it mostly dead (like in the Princess Bride).

Time to move on and cut my losses. I could spend hours probing around for clues with my scope but I have other (not DigiX) boards I can use and a project to continue with. May have to shoehorn a ESP8266 to a Mega or bring up my newly acquired ESP32 dev board.

The ironic thing is this all started because I could not connect to wifi which I ultimately did by configuring the chip directly using AT commands while the MCU was off the board. Had I not been sent down the path of fighting with Wifi, and messing with power options, I'd still have my DigiX.

If anyone is bored with their working DigiX or have more than they need PM me.

Thanks to Solice and PeterF for your encouragement and tips, but it's time to move on.
« Last Edit: January 31, 2017, 09:01:32 pm by exeng »