repairing traces...on a fine pitch board?

[eccerr0r]

Well I need to repair a trace... ... on a DIMM.

These tracks are tiny! What, hair line traces?

Fortunately the track is fairly long, maybe 1cm, and fortunately 1mm away from the next trace. Now I need to remove the soldermask. However this trace must be thin from top to substrate as well, how could I guarantee mechanical scraping wont abrade the track? What would one use to scrape off the soldermask for these hairline traces?

I guess the next thing after removing the solder mask is that the track needs to be jumpered. 30AWG Kynar wire is huge compared to this track...

[diif]

I use a scalpel blade, 0.1mm jumper wire and a stereo microscope.

[eccerr0r]

Scalpel blade... no check
$1 CCC Xacto knife... check

0.1mm jumper wire... no check
30 AWG wire... check

Stereo microscope... no check
1.4x magnifier light... check

All ready to fail! *sigh*

[megaraider]

Consider another approach:
don´t fix the trace... just wire end to end.

[eccerr0r]

Unfortunately the ends are pads under BGA components...

[stj]

rossman has fixed that a few times on video - he uses very fine wire and puts a loop on the end to hold the bga ball

[gabiz_ro]

You may find some thin wire to use in some like phone earpiece, vibramotor.
As for visual,you may try some camera on phone or tablets with some attached lens.Need to experiment a little.

[eccerr0r]

Well, I guess the BGA doesn't matter, the break is nowhere near the BGA...
Need to think of a better source of wire that's not coated with varnish...or oxidation for that matter.

[stj]

i just strip some stranded copper wire for such work
usually from an old pc psu!

[megaraider]

Originally Posted by eccerr0r

Unfortunately the ends are pads under BGA components...
Well, I guess the BGA doesn't matter, the break is nowhere near the BGA...

And vias are another option...

Originally Posted by eccerr0r

Need to think of a better source of wire that's not coated with varnish...or oxidation for that matter.

Originally Posted by stj

i just strip some stranded copper wire for such work
usually from an old pc psu!

Also my favorite solution

[eccerr0r]

Triumphant(for now!) Used 30AWG wire and cheap crap orange flux that I had lying around...

DDR2-5333 DIMM module seems to work once more at least at DDR2-3200 speeds...

Now whether or not I dab some CA or epoxy over it to protect it...

[eccerr0r]

It sticks!

That's a 30AWG underneath that blob, and a 10¢ piece under the board.

Fortunately the tracks were relatively far apart, and only one track.

[megaraider]

Originally Posted by eccerr0r

Triumphant(for now!) Used 30AWG wire and cheap crap orange flux that I had lying around...
DDR2-5333 DIMM module seems to work once more at least at DDR2-3200 speeds...
Now whether or not I dab some CA or epoxy over it to protect it...

Originally Posted by eccerr0r

It sticks!
That's a 30AWG underneath that blob, and a 10¢ piece under the board.
Fortunately the tracks were relatively far apart, and only one track.

Great
(although i would have gone with a thinner wire)

[ChaosLegionnaire]

what a nice pointless repair! momaka will be proud! do post the link to this thread in the pointless repairs thread!

[eccerr0r]

Don't worry I have another one i need to fix.

[stj]

Originally Posted by ChaosLegionnaire

what a nice pointless repair! momaka will be proud! do post the link to this thread in the pointless repairs thread!

pointless?
do you know how expensive used dimms are becoming?

new stuff costs far less than used ddr or ddr2.

[eccerr0r]

Current dilemma : cannot get debug information from a dead 512M DDR2 module.

Need parts for a 2G DDR2 module that I rootcaused a failure.

Sacrifice pointless 512M module to fix a much more useful 2G module?

Should add why I even want to repair this 512M module: because without it, I'd have an odd number of 512M modules... there's this machine that has three working 512M modules in it right now...

[megaraider]

Originally Posted by ChaosLegionnaire

what a nice pointless repair! momaka will be proud! do post the link to this thread in the pointless repairs thread!

Originally Posted by stj

pointless?
do you know how expensive used dimms are becoming?
new stuff costs far less than used ddr or ddr2.

IMO this is an excellent example of forum member misbehaviour
[Most forum moderators would have block you @ChaosLegionnaire without any warning]

[megaraider]

Originally Posted by eccerr0r

Current dilemma : cannot get debug information from a dead 512M DDR2 module.

Need parts for a 2G DDR2 module that I rootcaused a failure.

Sacrifice pointless 512M module to fix a much more useful 2G module?

Should add why I even want to repair this 512M module: because without it, I'd have an odd number of 512M modules... there's this machine that has three working 512M modules in it right now...

Better to have an odd 2GB than an odd 512MB module
(Providing motherboard RAM size is not limited to less)

[eccerr0r]

Yeah, definitely, though repairing this module would go with the above module and the number of 2G modules would be even once more...

Anyway, this machine with three 512M modules will not get 3.5GB (3200MB ... chipset limitation)... 3GB maybe, when I pull the 1G modules out of the other machines to stuff these repaired 2G modules in.