How do I solder this?

musicman282

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So, I accidentally snapped some of the blades off the cpu fan on my 1940-in-1 board. This caused the board to vibrate pretty badly and it vibrated off the table :crying:

Well everything seems to work, but now the option buttons don't work that allow me to access the test menu. I've narrowed it down to this gouge in the trace on the bottom right next to the PLC. How do I go about repairing this? I just wonder if some experienced SMD people can weigh in on it. Do I just use a really small tip on my soldering iron and attempt to solder a jumper to the pin? Any suggestions?



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I would buzz the tracks through first, the scratch may look very nasty but it might only be through the board laquer, am always surprise at how nasty some scratches can look yet still have full connectivity through them.
 
Your safest method is to use Kynar wire (very thin) and run it from one of the pins to wherever the trace goes. Find the next thing that's soldered that the trace runs to. You can verify your findings with a multimeter on continuity test. I've had some success getting the multimeter to connect to the area where a trace is broken, you can grab a sliver of the exposed trace, enough to find the destination. It helps to have really sharp multimeter leads.

Also, you can follow the trace visually to a via (through the board). A lot of times you can get a multimeter lead to connect at the vias. I've had limited success (notably on XBox 1 hacks) connecting solder at the vias.

Sometimes you can scrape away the blue mask and get to the copper trace and tack solder to it, but this method is more destructive to the board and rife with potential issues.

Edit: I would also check that lead coming off of the chip, second lead from the right side on the bottom of the chip (pin 29). Doesn't look like it goes anywhere, but could hit a via under the chip. I use some "probes" I got from RadioShack back in the day, they are basically dental picks. Gently see if the chip leg moves independent of the board when probing at it. Use a magnifying glass and some good lighting.
 
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Gently scrape away the soldermask on either side of the break, then cut a short run of wirewrap hookup wire and tack it across the gap.

1. Scrape away mask
2. Apply flux, then pre-tin both sides of the break
3. Solder on the shunt
4. Apply solvent and clean
5. Check continuity between the break, and among the neighboring traces

Takes some practice, but once you get it down you end up with a nice-looking repair.
 
Thanks for the help guys. I already checked continuity and the traces are definitely broken. I never thought about scraping away the solder mask. I'd feel a lot more comfortable doing that than trying to solder the PLC. I feel like I don't have a steady enough hand to not cause some solder bridges between pins. What's the best method for scraping off the solder mask? Xacto? Can I use clear epoxy to cover the repaired traces and make the repair more permanent?
 
Use a sharp xacto. If any of the traces have delaminated from the substrate, then cut those parts away before you do the repair. You can epoxy afterward, but not necessary so long as you re-tin any bare copper.
 
You will need to add a small piece of wire as suggested above, trying to make solder alone bridge the gap wont work 9 times out of 10.
 
+1 on a bridge wire. Crossing a gap with solder alone is an iffy proposition.

Anyone ever tried those conductive glues/epoxies for a repair like this?
 
Anyone ever tried those conductive glues/epoxies for a repair like this?


Yeah..its a waste of money. I tried some stuff that you used like a pen to just connect broken traces. It never worked and I ended up just doing the old school wire repair.
 
Looks like you have three traces to repair and they look large enough that you can repair with wire or resistor lead.

How did you break the fan blades?
 
Looks like you have three traces to repair and they look large enough that you can repair with wire or resistor lead.

How did you break the fan blades?

More than just that. Is it me or does it look like that scrape reaches one of the pins on the FPGA? Make sure that pin still has continuity where it should and that it's not shorted to a neighboring pin.
 
You can also use a Fiberglass Pen to remove the mask. A lot less scary then scraping away at it with an Xacto blade. ~$5 at Rat Shack.
 
You can also use a Fiberglass Pen to remove the mask. A lot less scary then scraping away at it with an Xacto blade. ~$5 at Rat Shack.

I might try that first. Thanks for the tip. I wont shop at radio shack anymore. Last time I was there they demanded my address and phone number and I said I didn't have either. Then they told me they cant make a sale without it. I order everything online now. Its worth the wait to give them anymore of my money.
 
Last time I was there they demanded my address and phone number and I said I didn't have either.

Grab one of their business card and give them the info on that. They love that kind of thing! They don't need your phone number to ring up a sale, it is your privacy and you don't know what they will do with that info.
 
I wont shop at radio shack anymore. Last time I was there they demanded my address and phone number and I said I didn't have either. Then they told me they cant make a sale without it.

I would ask to speak with the manager. Radio Shack policy is to ask, but I have never had anyone give me any crap over declining. FWIW, I don't decline at the local one because I want the sale paper, but do elsewhere.
 
I might try that first. Thanks for the tip. I wont shop at radio shack anymore. Last time I was there they demanded my address and phone number and I said I didn't have either. Then they told me they cant make a sale without it. I order everything online now. Its worth the wait to give them anymore of my money.

My response:

My address is 1 NO ADDRESS ROAD, ANYCITY, CA 98911. Phone number is 208-867-5309.
 
My response:

My address is 1 NO ADDRESS ROAD, ANYCITY, CA 98911. Phone number is 208-867-5309.

Wish i was that clever at the time. I was already irritated at their prices. Forcing my address was the breaking point. I already get a ton of junk mail.
 
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