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]

Re: repairing traces...on a fine pitch board?

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

[eccerr0r]

Re: repairing traces...on a fine pitch board?

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]

Re: repairing traces...on a fine pitch board?

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

[eccerr0r]

Re: repairing traces...on a fine pitch board?

Unfortunately the ends are pads under BGA components...

[stj]

Re: repairing traces...on a fine pitch board?

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]

Re: repairing traces...on a fine pitch board?

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]

Re: repairing traces...on a fine pitch board?

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]

Re: repairing traces...on a fine pitch board?

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

[megaraider]

Re: repairing traces...on a fine pitch board?

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...

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

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

Also my favorite solution

[eccerr0r]

Re: repairing traces...on a fine pitch board?

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]

Re: repairing traces...on a fine pitch board?

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]

Re: repairing traces...on a fine pitch board?

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...

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]

Re: repairing traces...on a fine pitch board?

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

[eccerr0r]

Re: repairing traces...on a fine pitch board?

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

[stj]

Re: repairing traces...on a fine pitch board?

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]

Re: repairing traces...on a fine pitch board?

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]

Re: repairing traces...on a fine pitch board?

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.

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

[megaraider]

Re: repairing traces...on a fine pitch board?

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]

Re: repairing traces...on a fine pitch board?

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.