repairing damaged PCB traces

[puppet]

Awhile ago I attempted to remove a HSF off one of my GF DDRs. I thought I was being careful with the screwdriver in trying to twist it off. All I managed to do was spoil the card. I had another handy so I put him back in the drawer.....until yesterday. Put it in the freezer and popped off the HSF.....wish I'd done this before.

While I didn't realize it then I do now.......never ever pry or twist any sharp object directly against the PCB. Without some sort of backing ie. credit card.....you run a very real risk of breaking a trace.

Thats what happened to me......a few. Funny, what looks like a small nick to the naked eye.... under 100x magnification I can see the "canyons" I created between the traces. I don't have the equipment to "bead" out the PCB to expose more of the wire....and it's pretty close to the GPU.

Has anyone here done a repair like this with a "liquid" conductor? Something that could be applied with a pin point and harden...joining the gap. Any tips on this would be great. I'm thinking that this is all that keeps the vid card from running again.

thx

 

[Shadow ÒÓ]

Once blew out an amp in my car stereo. It literally blew a small chunk off of my board. I followed the traces to where they started and soldered one strand of a 14 guage wire to it.......then to the other end it was supposed to connect to. It worked fine till I sold the car.

I used silacone to insulate the hair fine wires also.

It was a very expensive Kenwood head unit and I was determined it could be fixed.

 

[Phil]

My dad did something very similar to that on a car stereo shadow. He really is a master with the soldering iron, he did it with a plain ordinairy 25W harware store 2mm wide nib iron as well.
Repairs like that on a video card would not be so simple, it won't hurt to try but I'd say the chances are slim. Maybe using a conductive pen would do it

 

[puppet]

This is small......soldering,for me at least,is out of the question.

Do the conductive pens leave a small amount of material to fill gaps or just paint a trace?
I'm looking at this under a microscope so my interpretation of the gaps are probably exagerated.
If I can do the actual repair with the aid of the scope it should work. I'd heard about that window defogger repair "paint". Have you fellas any experience with that?

The way I see it.....the card can't be any worse than it is now. hehehe , it would be a real kick to get it working again.

I did a search on the web berore posting this and ran across a fella that repairs arcade system boards. The boards shown had sections that were eaten by acid and/or corroded. Amazing that something like that could be repaired. Real talent. After seeing that......it made my repair pale by comparision.

 

[goman]

I have never repaired a vid card befor but I do have experience in personal pc board repair and I have used the Rear window defogger kit to do a couple of them. What I did was sharpen a tooth pick with a rasor blade and paint it on with that you wil have to sharpen it to the sharpest point you can get and for sure have a steady hand. Hope this helps!!

 

[Shadow ÒÓ]

puppet, if all else fails, and you decide to get rid of the card, I'd like to take a shot at repairing it.

Also, I'd be interested in seeing the link you mentioned of the guy who repairs arcade boards.

 

[puppet]

goman......that sounds like a plan. I'll let you guys know if it works out ,,,,,or not.

Here ya go Shadow ÒÓ

http://www.repairconnection.com/acid_damaged_mpu.htm

 

[LimeyGreg]

Hey Puppet, Shadow is going to LA, just send it to me and I'll see he gets it ???.

How far apart are the traces? Get some blue painters masking tape and put a strip on some glass. Draw as many lines at the same distance apart as you cut, make the lines long enough to bridge the nicks plus a bit. Now using a sharp Exacto knife cut out the pencil lines - you are making a mask.

Now use some fine emery cloth over the end of the eraser of a pencil to remove the varnish where you damaged the card. Clean it with alcohol and lay your fabricated mask on the board to line up with the traces. Now apply the conductive paint (defogger repair paint) to the mask. Remove the mask before the paint dries, if you don't you may well pull it all off and have to start again.

If you can't cut the slots accurately enough then do one repair at a time. Just cut one slot, or use two pieces of tape applied very close to each other. Again, remove the tape before the paint dries but allow it to cure before you try the next repair.

 

[puppet]

LimeyGreg I see what your sayin'. hehehe.....I'm sure Shadow would get it too....

Lucky for me each nick only involved 1 trace. When I look at the areas.....it could of be a lot worse. The traces are grouped about 1/64" apart. Long and short of it is I could be less precise in the fix....but that would be lazy. Masking sounds like a good idea regardless. Actually your talking about a stencil of sorts....thats damn smart.
thx for the tips fellas.

If I can't get it to work.......I will donate it to "science".

 

[Phil]

Conductive pens just write in a conductive material, people use them to unlock athlons. I say go for it as it's better than writing it off, any chance of a picture of whats been done?

 

[puppet]

Phil
I tried a pic.........but it is so small it can't be picked up. I might try again with a buddies Nikon macro lens.

The spots in question look like small white dots. I by no means went "nuts" trying to get the HSF off.....just didn't use my head. If you've ever looked at a PCB @ 100x and looked at the printed component placement "labels".....they are composed of a series of white dots. The nicks I'm talking about are a little larger than that........damn small.
Unfortunately as they say......"spark don't jump that far".

 

[KILLorBE]

LimeyGreg gave me an idea, Solder doesn't like that kind of tape (blue painters masking tape) and as long as you have masked the surrounding area the solder would only stick on the place that needs to be soldered.This would be faster than a condutive pen.(and easier...at least for me).
Naaaah I think I wouldn't use tape but I would solder it right away.
I would be happy to do it for you, to bad I don't live nearby.

 

[Blue Jester_2112]

If you do go ahead with trying to repair the card you might want to invest in something called "extra hands" if you don't already have one. They sell it at radio shack. It's basically a metal base with two arms with ball joints and alligator clips at the ends. They are great for holding and positioning small parts and it allows you to set up whatever your working on in a comfortable position an leave it there leaving both hands free to work with. It also has a small magnifying glass. I use one when I'm working on fine detail on sculptures and I like it alot. They run about $10 and might come in handy. Good luck fixin' your card.

 

[puppet]

Good advice........extra hands are nice. (good to know they don't have to be connected to my 14 yr old son...

 

[puppet]

Well today I laid my $10 down on the autoparts counter and returned home with the defogger repair juice. Spent an hour or so under the microscope and did my best to patch the 2-3 broken traces. Actually found it easier to drop a dot over the area and use a toothpick to clean up to the line. The "nick" provided a foundation for the paint and wouldn't hold on the slicker surrounding area. I used the scope to check my work.

I have the HSF off so I used caution in the system. Put him in and hit the switch........nothin'.
I quickly realized that I should plug the system in too... (minor detail)

Did that and it posted! It looks like I got lucky and he's fixed.
Thx to all your great tips' fellas. I'm off to buy a better HSF.

 

[KILLorBE]

Nice job

 

[puppet]

Well I cobbled together a HSF from some extra parts around the house and let the kids game on it for a few hours.

hehehe...testing complete.

On a side note.....looking @ the wafer the GPU is mounted on,under magnification,you get to really see why some people short out their vid cards with the AS2 epoxy/paste. The surface of the wafer has MANY small holes at the traces. The holes are just like the ones you can see on the PCB itself(in some of the traces) but MUCH smaller. I'm not sure of the purpose of these holes.....other that "testing" the board's trace connections. Filling these holes with some conductive paste/epoxy would be easy to do and tough to clean.

Add to the fact that when the wafers are cut, they are cut through the traces. The actual connection to the board occures just before the outside edge of the wafer......but the edge of the wafer has blunt cut traces.....all the way around. A little conductive paste wiped on the edge could short a half dozen or so traces. This edge......acting much like the end grain of wood......would be tough to clean to. Cutting the paste or epoxy with a fliud cleaner could even force it into the wafers edge......to stay.

I guess the bottom line is to be very careful with conductive pastes/epoxies.