Vacuum cleaners and PCBs

Zennmaster

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Just out of curiosity:

I know it's a widely held bit of wisdom that one should never use a Shop-Vac with a dusting attachment to clean a PCB, because there is a risk of a static discharge causing all kinds of death and destruction.

It is also a widely held bit of wisdom that one should never use water to clean a PCB, because the tiny little bits of mineral (unless we're talking about distilled water) could be conductive, and thus cause a short, again causing all kinds of death and destruction.

My own experience, as well as that of those who I think of as legitimate experts in the field find the point about water to be such a low risk as to be safely ignored (assuming the PCB is properly dried).

On the other hand, I have very little experience or information on the vacuum thing.

Has anyone ever actually seen a PCB destroyed by a static discharge from a vacuum cleaner?

I ask because I recently invested in a small Shop Vac with the teeny attachment set for use in cleaning pinball playfields. It sure looks like it would be a great way to get rid of the loose stuff on dirty PCBs, and to keep them from crusting over in the first place.

If the collected wisdom here says it's a real risk, then I won't do it. On the other hand, if this is another "Old wives' tale", it would sure be a nice way to keep a board clean without even the need to remove it.
 
It is also a widely held bit of wisdom that one should never use water to clean a PCB, because the tiny little bits of mineral (unless we're talking about distilled water) could be conductive, and thus cause a short, again causing all kinds of death and destruction.

I've washed a couple PCBs by scrubbing the board with simple green and a paint brush. Then hosed it it off with good 'ol fashioned garden hose water. (make sure you leave your kids' water balloon tip on the hose end :) )Just have to remove any socketed chips and let the board dry before using it again. No issues thus far. #fearless

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Heck some people throw them in their dishwasher...

Couldn't advise you with the vacuume. But with some of the PCBs I have cleaned, a vacuum would have never got the board clean.
 
I wash all boards I refurb, similar to above, with Greased Lightning and a paintbrush.

I also will vacuum off boards that are dusty from sitting (i.e., ones that have already been washed, but have been sitting around for a while). I use my Dyson, with the brush attachment.

I've done it to literally hundreds of boards, without a single issue.

Some electronics are legitimately static sensitive. TTL stuff is fairly robust though.

Wash your stuff.
 
I also will vacuum off boards that are dusty from sitting (i.e., ones that have already been washed, but have been sitting around for a while). I use my Dyson, with the brush attachment.

...
Wash your stuff.

I was hoping you'd weigh in, as you are among those I mentioned being legitimate experts. I've definitely had great luck with mild solvents (IE: Simple Green) and water, but it seems like overkill to pull and wash a board as part of, say annual maintenance.

The reason behind the timing of my question is that I've just had some concrete work done in my basement, and despite plastic sheeting and moving blankets on the games, the dust got EVERYWHERE. Given the nature of the stuff, I'm hesitant to use any wet method for removal, as anything that gets missed will end up in a much more solid state than when it started. On the other hand, the Shop Vac with the dusting brush does a fantastic job.

Again, thanks for the advice!
 
I've washed a couple PCBs by scrubbing the board with simple green and a paint brush.
...

Couldn't advise you with the vacuume. But with some of the PCBs I have cleaned, a vacuum would have never got the board clean.

I've had great luck with the "Wet method" as well, which is why I pointed out that despite being well-accepted, the concerns are generally unfounded.

Nice pics! :)
 
If that's the case, one other thing that you may want to look into is a horsehair brush, for the vacuum.

I have one, which came from a vacuum we had when I was a kid. It definitely does a better job at getting fine dust off. The Dyson one works ok for regular dust, but the horsehair is better for finer stuff.

Oh look, here's a deal for a 2-pack of them:

https://www.ebay.com/itm/391415261299
 
I also wash boards and I have very mineraly well water. I have no issues nor would I expect to. That said I always air dry naturally and don't put in a dish washer
 
Air compressor and air nozzle should blow everything clean. just watch the labels. I do it all the time if I want to keep them dry. if not the wet method works great.
 
I always clean boards with Simple Green, a paint brush and water. I suspect the mineral deposit argument is more likely with newer electronics with much finer pitch components.

I'm going to respectfully disagree about the use of a vacuum. Just don't do it. It generates massive amounts of charge. Instead spend the less that 20 minutes you might be vacuuming and simply search the good old interwebs on ESD.

ESD does LOTS of damage that you don't see until later in the components life.

There isn't enough Concrete dust on the boards to make a difference with washing (assuming dust from bags being mixed on site). If it's dust from cut concrete it's not going to re-cure with the addition of water. It's a chemical process so it will just rinse away. Use the paint brush with mild soap and rinse and blow dry.

I was hoping you'd weigh in, as you are among those I mentioned being legitimate experts. I've definitely had great luck with mild solvents (IE: Simple Green) and water, but it seems like overkill to pull and wash a board as part of, say annual maintenance.

The reason behind the timing of my question is that I've just had some concrete work done in my basement, and despite plastic sheeting and moving blankets on the games, the dust got EVERYWHERE. Given the nature of the stuff, I'm hesitant to use any wet method for removal, as anything that gets missed will end up in a much more solid state than when it started. On the other hand, the Shop Vac with the dusting brush does a fantastic job.

Again, thanks for the advice!
 
Experiences will vary. I wouldn't worry about tap or well water generally, the amount of minerals is fairly small. If you are worried at all, use distilled.

As for vacuum cleaners.... I'd be a bit more hesitant myself. TTL is fairly robust, but I had a working board shipped to me in bubblewrap (and there may have been peanuts outside the wrap, I can't recall now). The CPU did take a hit as the board was no longer working on arrival. Can't say what did it (could have been the shipper during packing, could have been the bubblewrap exacerbated by the possible peanuts, etc). Static can damage them, but it needs to be a certain amount (varies based on component), and needs to be delivered to the 'right place'.

That said, those that handle far more boards than I, that have already chimed in are speaking from experience, and that counts for a lot in my book. I likely won't ever reach the board count some of these guys have worked on.... so while I might not do the same out of caution, I trust in their experiences. I just know the day I pop a $12, $20, or higher value chip from static that I'll be upset with myself for not taking some precautions (Murphy is a bitch).

I still don't think I'd use a vacuum cleaner or regular compressed air on them. If I need to use air/light dusting, I'll used 'canned air' (which isn't air) which is meant for cleaning computers/etc.

Whenever I do repairs for people, I try to always use a static bag when I return a board, as I want to give the board its best chance of surviving any static events until it gets puled out of that bag.
 
There isn't enough Concrete dust on the boards to make a difference with washing (assuming dust from bags being mixed on site). If it's dust from cut concrete it's not going to re-cure with the addition of water. It's a chemical process so it will just rinse away.

I have a lot of evidence that suggests otherwise. It's not what would be recognizable as concrete, but it forms a very persistent sort of "dry mud" that is resistant to, for example, wet mopping and other "standard" forms of cleaning. Bad, bad, nasty stuff...
 
....get a turkey roaster pan and toss in simple green and a waterproof adult toy.

Instant poor mans ultra sonic cleaner.



LoL


I hand wash with concentrate simple green, air dry with a compressor or out in the texas sun in summer. 2 hrs at 110+F its dry
 
I have a lot of evidence that suggests otherwise. It's not what would be recognizable as concrete, but it forms a very persistent sort of "dry mud" that is resistant to, for example, wet mopping and other "standard" forms of cleaning. Bad, bad, nasty stuff...

I understand the prospects of cleaning that up, it's a lot like drywall dust in how it gets into everything. But You're not wet moping the boards, your flushing them with water and using a paintbrush to loosen up the crud. Completely different.
 
Static can damage them, but it needs to be a certain amount (varies based on component), and needs to be delivered to the 'right place'.

That said, those that handle far more boards than I, that have already chimed in are speaking from experience, and that counts for a lot in my book. I likely won't ever reach the board count some of these guys have worked on.... so while I might not do the same out of caution, I trust in their experiences. I just know the day I pop a $12, $20, or higher value chip from static that I'll be upset with myself for not taking some precautions (Murphy is a bitch).

Unfortunately ESD is real and so easy to ignore with experience related anecdotal evidence mixed in with some truth. The shock you experience is not the only time you create static discharge. Damage is cumulative and not necessarily immediate. Companies spend a ton of cash on ESD mitigation systems and training for a good reason.
 
Thanks everyone for all the input, that's some great thoughts and interesting ideas.

However, so far, no one has answered "Yes" to the actual question I asked:

Has anyone ever actually seen a PCB destroyed by a static discharge from a vacuum cleaner?

I am now of the opinion that a small (2.5hp peak) Shop Vac with a small dusting brush is a low(but not zero)-risk proposition when it comes to frying arcade PCBs. Sure, the physics don't rule out a bad event, but like anything else, the risk has to be evaluated in context.

By way of analogy, I have a dust collection system in my woodshop that runs on 220VAC. Because of the concerns about fire danger from static discharge, I ran a ground wire through all the (4" PVC) ducting. That said, every verifiable shop fire incident that I was able to find involved much larger, essentially industrial applications where the conditions were much more favorable to fires than in my one-person shop.

So I'm going to use the setup that I use for pinball playfields (stepped down hose and 3/4" dusting brush), and I'll see what happens. I'll also keep to old, more rugged boards, and stay away form my current PC mobos, and pretty much anything with SMD components. :) I tend to worry about things, so I may also look into rigging up some form of grounding protection, just in case. If anything gets damaged, I'll be sure to sing out about it. :)

Thanks again!
 
If anything gets damaged, I'll be sure to sing out about it. :)

Thanks again!

You're free to do whatever you want but you entirely missed the point so I will reiterate in an attempt to limit the disinformation.

With ESD, just because you can't see/feel it dosen't mean it didn't damage anything.
 
You're free to do whatever you want but you entirely missed the point so I will reiterate in an attempt to limit the disinformation.

With ESD, just because you can't see/feel it dosen't mean it didn't damage anything.

And ... ESD damage may not be evident right away and destroy the parts. It may have just affected longer-term life/reliability. You cannot "see" it ... unless perhaps you Xray the dies in all the ICs etc. The board might work as expected after cleaning, then for a week or months or years ... but theoretically, it has been compromised, and may fail at anytime. One cannot predict when (or even "if" damage was done due to ESD with limited resources available for testing such damage).
 
You're free to do whatever you want but you entirely missed the point so I will reiterate in an attempt to limit the disinformation.

With ESD, just because you can't see/feel it dosen't mean it didn't damage anything.

No, I didn't miss your point, I folded it into my risk assessment. There are all kinds of things that can cause TTL chips to fail, and in my experience, PCB repair is a matter of tracking down where a failure has occurred and replacing whatever is broken. If it's broken because it got cleaned once a year with a vacuum, or because something conductive ended up somewhere it shouldn't have, or if just one too many electrons got pushed through, I'm not sure what the difference really is, the result is the same.

Absent any quantitative data, I'm simply inclined to accept the risk-reward balance involved in keeping a PCB clean against the possibility that some non-obvious damage may or may not be taking place.

Well-respected PCB repair folks in this community use techniques that are considered by some to be anywhere from controversial to butchery, and as perfectly acceptable by others. In nearly every case, there is potential for long-term accelerated wear or failure. This is just the game we play when we keep these old games running.

Edit: I just re-read this post, and it sounds way more argumentative than I intended it to be. All I mean to say is that it seems that there is little hard data (or even anecdotal data) to suggest what the rate and level of damage might be, vs the known benefit of keeping a board clean (even if it's just the emotional warm and fuzzy). In my judgment, it's a risk that seems appropriate, as long as appropriate caution is observed.
 
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If the collected wisdom here says it's a real risk, then I won't do it. On the other hand, if this is another "Old wives' tale", it would sure be a nice way to keep a board clean without even the need to remove it.

There is plenty of information on ESD on the internet which obviously debunks it as an "Old wives' tale", seems odd that you don't spend the small amount of effort to actually look it up.

However, so far, no one has answered "Yes" to the actual question I asked:
Has anyone ever actually seen a PCB destroyed by a static discharge from a vacuum cleaner?

This is a ridiculous question which bears no value. You are ignoring that ESD failures predominantly effect lifetime in a non catastrophic way. This question is predisposed to result in the answer No.

Has anyone ever actually seen a PCB destroyed by a static discharge from a vacuum cleaner?
No.
No. No. No.

Perfect case in point as It's unlikely to fail at the moment of vacuuming.

To which I might add - How are you sure? At what point did you make sure that a board you vacuumed has survived its expected lifetime and if it hasn't have you run failure analysis on the component to ensure it wasn't ESD related?

No, I didn't miss your point, I folded it into my risk assessment. There are all kinds of things that can cause TTL chips to fail, and in my experience, PCB repair is a matter of tracking down where a failure has occurred and replacing whatever is broken. If it's broken because it got cleaned once a year with a vacuum, or because something conductive ended up somewhere it shouldn't have, or if just one too many electrons got pushed through, I'm not sure what the difference really is, the result is the same.

I guess you are correct, you didn't miss my point, you dismissed it. Doesn't sound like risk assessment to me.. more like fishing for the answer required to make one content with their choice. Which I might add, you are welcome to do, it's your prerogative. Just don't try to make it sound like you made a decision based on data or evidence.

Absent any quantitative data, I'm simply inclined to accept the risk-reward balance involved in keeping a PCB clean against the possibility that some non-obvious damage may or may not be taking place.

You should look up the difference between quantitative and qualitative data. You don't seem to be interested in quantitative data - you are not asking for numbers and measurements. You are asking for folks feedback about their experiences (qualitative). If you were interested in numbers (quantitative) a simple google search would have answered your question.

Well-respected PCB repair folks in this community use techniques that are considered by some to be anywhere from controversial to butchery, and as perfectly acceptable by others. In nearly every case, there is potential for long-term accelerated wear or failure. This is just the game we play when we keep these old games running.

IMO You are just looking for the easy way out and to feel good about it. No this isn't the game we play, it's the game you play. You either take the proper steps or you don't. It's that simple. Don't ask what you should do and when you don't like the answer make it sound like there isn't any problem and it's just overblown hype.
 
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