If you've only used it on the legs of a couple of chips like U1, you'll probably get away with desoldering the wires (they are FUBARed as it will have wicked up between the strands and you cant get it out), then washing the area thoroughly, scrubbing with a natural fibre bristle brush, first with Isopropyl alcohol (IPA) to remove rosin and grease, then with really hot water with a trace of unscented liquid dish detergent to attempt to remove the chlorides, then with distilled (or deionised) water to remove detergent and mineral traces, then with IPA again to remove as much water as possible. Blot up as much of the water as possible with a lint-free wipe before the final IPA rinse. Blot up the IPA and either dry for 24H in a warm place before you reapply power, or dry *THOROUGHLY* with hot air (no more than 95 deg C) once the residual IPA has evaporated.
I already have a bottle of isopropyl alcohol. I checked the safety datasheet and it says "more than 75%" purity. Is that good enough?
Alternatively I can buy a spray cleaner called
PRF 6-68 Kontakt which is described as follows:
Contact cleaner, removes all kind of rosin flux, oxide, sulfide, dirt and oil. Non-conductive. Application: Television and VCR sets, telephone, electronics, office machinery. Brush is extra accessory.The safety datasheet says it contains 40-50% naphta.
Alternatively there's another spray cleaner called
PRF IPA containing 40-60% isopropyl alcohol is described as follows:
All-round cleaner for electronics. Pure isopropanol, which removes dirt, oil, grease and resin from printed circuits, magnet heads as well as from the parts of fine mechanics and optics. Brush is extraFinally I can buy a bottle of 99.5% pure isopropyl alcohol.
Regarding distilled water -is that the same thing as sterile water which can be bought at the local pharmacy?
How much time do I have between when I soldered using the (acidic) flux and when it actually does damage to the PCB/components? I probably won't be able to get my hands on the above until over the weekend, but I can start mechanically brushing away the remains with an old toothbrush and the isopropyl alcohol (75% purity) right away if that'll do for now.
When you redo it, use the type of silver plated Kynar wire you found on Ebay, (for low voltage low current board patching, its much easier to work with than stranded)
So they're easier to solder on because the strands don't spread all over the place? And I'm guessing they're relatively stiff wires as used in the example Atari arcade board image posted by @rt, but in my case most of the wires go to a connector on an add-on PCB (plugs into a PLCC socket), so wouldn't basic stranded wires be better for that? I bought some "
dupont jumper wires" and exchanged the single connectors with one 5-pin connector header similar to the one shows attached here and soldered the ends of each wire to the applicable IC pins on the computer PCB.
Unfortunately I made another huge mistake apart from using the wrong flux. After soldering/wrapping the wires in place I secured everything using bathroom grade silicone. I just learnt that this is also harmful to the components/PCB, so I've mechanically removed it all (fortunately it wasn't totally cured so it was just sticky enough to remove easily. I suppose the liquids you've suggested above will remove any remains (I'm guessing there are invisible remains there even though the actual silicone has been removed). I also made the same mistake with some other PCBs a few weeks ago, so hopefully it's not so acidic that it'll create damage in that amount of time if I remove it now.
and use electronics grade liquid R or RMA rosin based flux (as the dry residue is nearly totally inert) - Do NOT use RA flux (acid and/or chlorides again), and I'd also avoid any paste or gel flux so you don't have to repeat washing the board.
Good advice! I'll be returning the flux I already bough as they ill-informed me. Thankfully there are forums like these around
I don't know where I can get electronics graded flux locally but I'll ask around in some local electronics forum. Given all the fake, low quality stuff available on eBay (or similar sites) it's probably not worth ordering from there.
Due to the lack of vertical clearance, you *WILL* need to solder to the socketed chip pins, and for a novice this is best done with the chips out and tilted at 45 deg, legs up so the solder doesn't run down from the pin shoulder onto the pin itself, or worse, if done in-situ solder the leg into the socket. Take extreme care removing the chip(s) - if you bend a leg it weakens them considerably and you *really* don't want to break one.
That's true. So wrap the wire around the top-part of the IC leg in question and quickly (as to not over-heat it) solder it? I should probably clean the IC leg thoroughly with a fibreglass pen etc. as I believe was suggested earlier as well, so solder attaches more easily (and thus less heat is transferred to the IC).
3M VHB tape is most usually found as a black self-adhesive foam tape sold for exterior use. Its commonly used for attaching car numberplates. Unlike other foam tapes, its adhesive doesn't dry up and drop off as it ages.
Do you have a link or part number? I could contact 3M directly about it.
Not drying up and dropping off is a good point which I would probably have overlooked. Good advice again!