Macintosh LC II Recapping and Dishwasher - please don't!

[Trash80toHP_Mini]

I've done countless of caps and never lifted a pad by twisting it exactly 180° twist.

From a mechanical standpoint, you're shearing the leads while putting little to no vertical tension on the pads, makes sense to me. How do you remove the tiny SMT caps?

 

[trag]

It seems to me that if one does a thorough Distilled Water rinse after a Dishwasher cleanse, that should take care of any dissolved minerals in the tap water used by the dishwasher.

Everyone seems to have their favorite methods and some of them may not be ideal (perhaps none of them) but all the methods seem to work well for a bunch of people based on the reports we read.

I'm made nervous by the twisting and cutting of caps.   But then, I've never had any trouble with lifted pads when simply desoldering caps.   That said, based on all the glowing reviews from folks who use twisiting or cutting, I must conclude that those methods work well too.

 

[olePigeon]

I use snips to cut the top of the caps off.  Sometimes they're so dried and loose they just slip off the leads.  Desoldering the ones that didn't immediately come off is simple without 3/4 of the can on there.

@Crutch Regular tap water potentially has minerals in it that can be corrosive to electronics.  Even if you dry it off completely, it may leave mineral deposits after drying.  This could lead to corrosion.  Ideally you want to use deionized water or alcohol for cleaning and rinsing electronics.  You can probably get away with an initial wash in tap water (such as in a dishwasher), but you'd want to do a final rinse with deionized water or alcohol.

 

[techknight]

I use a cheapo ultrasonic chinese special with distilled water (all I can get locally) and I have had ZERO issues. And this is with production PCBs at work. Never once have mineral deposits have been a thing or residues, etc. 

After it comes out of the ultrasonic cleaner, it gets a dip in the IPA to displace the water, and then it goes into the oven. Works every time. 

 

[johnklos]

it gets a dip in the IPA to displace the water

You're not talking about beer, are you?

I was given a severely corroded LC II motherboard which I thought might never run again. Since the capacitor goo ate away some of the traces, some came up a bit simply from cutting the leads. I washed the board with soap and water, with baking soda to neutralize any acid and to act as a surfactant, then vinegar to remove any minerals, then with distilled water to remove any vinegar. I also used toothpaste and a toothbrush to physically remove gunk and corrosion. I then repaired all traces, installed new caps and tried it out. Guess what? In spite of the poor state, it works!

It really all depends. If you have nothing to lose because a board doesn't work, then do whatever you have to do to clean it. But being aware of how minerals might affect things. If you have high mineral content in your area, then maybe dishwashing isn't a hot idea. If you have water softening or very low mineral content, then why not?

For removing caps, sometimes you can't help screwing things up no matter how hard you try. I have those precise needle nose side cutters which are meant for this very thing, but if the pads are literally floating on goo and corrosion, you just have to make due.

 

[Trash80toHP_Mini]

I'm not crazy about the notion of washing dishes after washing PCBs, but it's probably all right if you run it with soap and no dishes afterward.

I've always wondered why vinegar (acetic acid) is considered a proper agent for removing acidic gunk? A baking soda solution (base) sounds like a much better agent. Haven't got money for even a cheapo ultrasonic Chinese special, so I've been considering using the compressor and a detail gun loaded up with a series of solvents to "pressure wash" over around and under the ICs as well. Baking soda followed up with distilled water and then a final rinse with IPA seems a good approach. Whatcha think? Maybe use vinegar after the baking soda and then the distilled water?

A paint spray gun used as a pressure washer has to be better than using a dishwasher with so little oomph.

 

[LaPorta]

I use a cheapo ultrasonic chinese special with distilled water (all I can get locally) and I have had ZERO issues. And this is with production PCBs at work. Never once have mineral deposits have been a thing or residues, etc. 

After it comes out of the ultrasonic cleaner, it gets a dip in the IPA to displace the water, and then it goes into the oven. Works every time. 

Where do you obtain said cheapo Chinese special?

 

[johnklos]

I've always wondered why vinegar (acetic acid) is considered a proper agent for removing acidic gunk? A baking soda solution (base) sounds like a much better agent. Haven't got money for even a cheapo ultrasonic Chinese special, so I've been considering using the compressor and a detail gun loaded up with a series of solvents to "pressure wash" over around and under the ICs as well. Baking soda followed up with distilled water and then a final rinse with IPA seems a good approach. Whatcha think? Maybe use vinegar after the baking soda and then the distilled water?

I've always heard that the baking soda helps with anything acidic, but the vinegar is to remove any minerals after washing and cleaning. So yes, those, then distilled water with no minerals seems to make sense based on what I've been told.

What's IPA?

 

[Fizzbinn]

India Pale Ale. Not sure why folks recommend this type of beer for cleaning motherboards, always leaves my boards sticky... 

Kidding! Kidding!

Isopropyl Alcohol, I use the following with q-tips:

MG Chemicals 99.9% Isopropyl Alcohol Electronics Cleaner, 475 mL Trigger Spray Bottle https://www.amazon.com/dp/B004SPJP5O/ref=cm_sw_r_cp_tai_3HyHDb2HJJP2C

 

[Trash80toHP_Mini]

IPA was never intended to be good beer, it was developed to be drinkable beer after its long sea voyage to India. The good stuff (Porters) were just awful after arrival there, so they came up with IPA.

 

[techknight]

Where do you obtain said cheapo Chinese special?

eBay, where else? haha

 

[trag]

Some leakages, such as from an alkaline battery will be basic instead of acidic and so vinegar is an appropriate neutralizing agent.   I'm not sure where the pH of capacitor goo falls, or Lithium batteries for that matter.  I think the 1/2AA is some kind of lithium chemistry, or am I misremembering?

 

[error1]

I still think the dishwasher is a worthwhile final Hail Mary after hosing down a board with contact cleaner, manually scrubbing with IPA and vinegar didn't work, it's revived a lot of boards for me. No lead poisoning yet but I do run a bunch of machine cleaning cycles afterwards to get the worst electronics smell out of it   

The biggest downside of the dishwasher is probably that anything that gets knocked off the board is going down the drain never to be seen again. One of my 840av boards lost some tiny SMD components that way and I haven't been able to restore it.

An ultrasonic cleaner large enough to wash computer motherboards like that in is definitely on my wish list!