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Electronics => Beginners => Topic started by: Doctorkong on July 02, 2018, 02:13:44 pm

Title: How should I protect from electrostatic charges?
Post by: Doctorkong on July 02, 2018, 02:13:44 pm
Hello, I'm new here and I knew about this forum from the Youtube channel EEVBlog.

I'm looking for some info about how to protect my device but I really don't know how to get more info because maybe I'm the first one to ask about this problem.

I collect old videogames cartridges (like Super Nintendo, Sega Megadrive etc..). As you know some of them are getting really rare and expensive and since some of them are 25 years old today, I'm trying to find a way to protect these in the best way I can.

For most of them I don't want to be too meticulous but some of them are really rare and I don't want to let them to be ruined.

I'm going to protect them from UV light and electrostatic charge. To protect them from UV I use a rigid acrylic box that is made of PMMA. But, what should I do for electrostatic charges?

These cartridges are circuit boards with chips and a small battery (for saving game) in a plastic external shell. I was thinking about using antistatic bags but I have some doubts:

1) there are so many types that I don't know what to choose from.
2) do these bags protect the board even though it is included inside a plastic shell?
3) if I put this cartridge in a ESD bag and then in a PMMA box is it risky?

Sorry for my questions but I really don't know who can help me with my problem!
Thank you very much!
Title: Re: How should I protect from electrostatic charges?
Post by: CopperCone on July 02, 2018, 04:38:54 pm
This is complicated but shorting out all the io is a good start. Like when they sell ics they are usually jammed in black conductive foam. Then you handle the lossy foam and its a bit better. Otherwise you just wanna ground yourself
Title: Re: How should I protect from electrostatic charges?
Post by: JS on July 02, 2018, 05:29:51 pm
They should be protected already as they lived 25 years in this ugly world, so not extreme measurements should be needed. Shorting the output contacts might drain the battery as you don't know how they are connected, but it will keep them safe, so for games without a battery might be fine.

For games with batteries, yoou could look further to what you need or keep them connected to something wich provides ESD protection, but you would need a lot of connecrors to keep all your games protected. One option could be to have them in metalized bags as the ones components come in, and good be good to provide some grounding inside your plastic box, so all stay at gound potential and when you take them out aren't charged.

You should be careful while handling, that's the most risky moment, keep your consoles grounded, and ground yourself while handling. So now your ganes are stored at ground potential, your console is at ground potential when connecting the games and also are you while handling. Bare foot and antistatic floor mat or conductive floor could do. If you don't want to be bare foot, there are ESD safe shoes, ESD safe shoe accesories, with a band from inside to the floor or the classic wrist strap wich is kind of ok working on the bench but not so much to move around.

JS

Title: Re: How should I protect from electrostatic charges?
Post by: C on July 02, 2018, 05:42:08 pm
CopperCone's
& JS are good.

You learn and use good static part handling.
For example to move part from one conductive pad to second, you
Touch pad then while keeping touch pickup part.
Touch second pad then while keeping touch place part.
Each touch puts you at same charge as pad so you and part stay at same change.

Anti-static areas could be ground but are often a high resistance to drain the charge and not spark it.
A ground strap that would connect you to ground has a 1M series resistor. A ground mat has a high resistance surface.
 
 
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 02, 2018, 08:03:05 pm
Thank you so much. My question is: do you think that using a ESD bag ITSELF can damage the circuit board?
I don't know, maybe it can become dangerous for the circuit board if it is in contact with the circuit itself or with the plastic shell of the game.
I'm asking that because I really don't know the proprieties of those bags except that they are made like a Faraday cage. Can those bag become dangerous in some ways?

I don't own so many rare games. I would like to use the best method I can to preserve 3 or 4 of them so I can pay something more for a better protection since I don't have hundreds of games to protect.
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 02, 2018, 09:21:48 pm
I also would like to specify that my aim is to store those rare cartridges and not to use them frequently. I'm going to preserve them for their collectable value and not to play with them. The solution I'm going to find is for the long term storage.
I would like to use the PMMA acrylic box because it stops UV and for the cartridge itself I'm looking for a good solution. I heard that PET sleeves are conductive and not good for storing cirtuit boards.
Title: Re: How should I protect from electrostatic charges?
Post by: JS on July 03, 2018, 05:01:16 am
You could put the black foam into the fingers to protect it but you should change it every year or two, the thing gets nasty after a while.

The bags will protect the inside from outside discharges as well as preventing inside charge to build up. The foam on the fingers would help dissipate any charge from the pcb to the bag. Battery life shouldn't be a concern, in fact you should remove the batteries to prevent leakage and corrotion  which can ruin the pcb. Also check for any dirt inside, if there are flux residues or leaky caps you should clean that before storing.

JS

Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 03, 2018, 07:07:28 am
You could put the black foam into the fingers to protect it but you should change it every year or two, the thing gets nasty after a while.

The bags will protect the inside from outside discharges as well as preventing inside charge to build up. The foam on the fingers would help dissipate any charge from the pcb to the bag. Battery life shouldn't be a concern, in fact you should remove the batteries to prevent leakage and corrotion  which can ruin the pcb. Also check for any dirt inside, if there are flux residues or leaky caps you should clean that before storing.

JS

Thank you so much! You are very gentle! I saw these bags http://www.faradaydefense.com/premium-70mil/21-3pc-8x10-notebook-esd-emp-70mil-faraday-bags.html (http://www.faradaydefense.com/premium-70mil/21-3pc-8x10-notebook-esd-emp-70mil-faraday-bags.html)
Do you think they are ok for my needs?
Title: Re: How should I protect from electrostatic charges?
Post by: JS on July 03, 2018, 01:09:15 pm
They look like they could do, just a bit expensive, think farnell puts a single 20 cents component inside a pretty big one... They would be loosing ton of money if the value even resembles anything like this.

JS

Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 03, 2018, 03:25:16 pm
Thank you for the tips.

You told about battery leakage or draining. Do you think this battery can leak or be drained by the bag? I attach a photo. Are there other components that can leak?
I'm sorry for all of these questions but these are subjects just some expert can answer
Title: Re: How should I protect from electrostatic charges?
Post by: JS on July 03, 2018, 03:52:59 pm
  Those batteries don't leek as far as I know as they are solid, but they can generate corrosion if the board gets dirty and/or wet. The blue caps can leak, but you probably don't want to take those out for storage, you could protect the PCB with some conformal coating in case they leak but all that seems over kill. Not likely to get serious damage for stored PCBs without a battery, caps aren't very likely to leak when unpowered and if there is no power around corrosion isn't as bad as if there is some DC power around.
  Hence, taking out the battery and checking once every a few years should do. If you want to save the game achievements as if you have a very very high tetris score is the only reason to leave the battery in I guess.

JS
Title: Re: How should I protect from electrostatic charges?
Post by: innkeeper on July 03, 2018, 10:47:29 pm
Humidity control...
you don't want things to dry.
40%-60% is the range most assembly pants run at to keep esd from being a problem.
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 04, 2018, 12:31:11 am
  Those batteries don't leek as far as I know as they are solid, but they can generate corrosion if the board gets dirty and/or wet. The blue caps can leak, but you probably don't want to take those out for storage, you could protect the PCB with some conformal coating in case they leak but all that seems over kill. Not likely to get serious damage for stored PCBs without a battery, caps aren't very likely to leak when unpowered and if there is no power around corrosion isn't as bad as if there is some DC power around.
  Hence, taking out the battery and checking once every a few years should do. If you want to save the game achievements as if you have a very very high tetris score is the only reason to leave the battery in I guess.

JS

That's what I was thinking about. The only problem is that if I want to remove the battery I should desolder is and I don't want to damage or touch the original cart. Do you think that letting the battery on the board is too risky? If the battery will die it is not be a problem but corrosion of the PCB IS a problem. What's the best thing I can do if I want to keep the battery on?
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 04, 2018, 12:38:36 am
Humidity control...
you don't want things to dry.
40%-60% is the range most assembly pants run at to keep esd from being a problem.

Thank you for the answer. I heard that humidity would damage the PCB and a dry environment too. I would like to make my best to protect a pair of cartridges that are really rare without desoldering or modify them. It doesn't matter If there's an expensive solution, I'm looking for the best one I can
Title: Re: How should I protect from electrostatic charges?
Post by: helius on July 04, 2018, 01:10:50 am
As long as your electronics are inside an ESD bag, they will not be affected by electrostatic charges, so there is no requirement to raise the humidity in storage. To prevent possible corrosion from condensation, you can use silica gel packets which absorb moisture.
If you are keeping the plastic clamshell around the PCB, there is zero possibility of anything shorting to the ESD bag and removing the coin cell is not required. CR or BR type cells do not leak and they do not contain corrosive electrolyte.
Title: Re: How should I protect from electrostatic charges?
Post by: TERRA Operative on July 04, 2018, 06:57:01 am
I would put each cartridge into its own metallized Mylar 'zip-lock' bag along with a small desiccant bag to remove any humidity.
Then stack the pile of bagged cartridges into a black plastic tub to keep light out and put it somewhere cool.

Foam on the cartridge fingers is unnecessary IMO.
Title: Re: How should I protect from electrostatic charges?
Post by: McBryce on July 04, 2018, 01:12:47 pm
Hi Doctorkong,
          I own quite a few old cartridges for several systems (although I wouldn't describe myself as a collector). Static damage would be an extremely unlikely event with these cartridges as the contacts are well protected from finger touching etc. The only time I've ever seen one being damaged was during connection/disconnection from the console, at which time you'll have removed the anti-static bag anyway. If they are in a box and not being handled, there is zero chance of them being damaged from static. The biggest longterm risk to these "newer" cartridges (the older ones only contained a single EPROM) are the electrolytic capacitors which can leak and eat away at the copper tracks.

McBryce.
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 04, 2018, 02:45:42 pm
Thank you for the suggestions. How can be possible to avoid the capacitors to leak? From what I understand from experts like you the CR batteries cannot leak because they are solid. In fact I think that's true because I didn't see some real leakage, maybe corrosion because of water in contact with the battery.

My solution would be the ESD bag + acrylic box to protect them all. I don't know how to avoid capacitors to leak anyway
Title: Re: How should I protect from electrostatic charges?
Post by: helius on July 04, 2018, 03:00:54 pm
CR contents are not solid, but they are not harsh alkali like alkaline cells. Specs mention lithium perchlorate dissolved in organic solvents. Lithium perchlorate salt is neutral (since it is a salt of a strong acid (perchloric acid) and a strong base (lithium hydroxide)).

Electrolytic capacitors leak when their rubber seal (the bung) is breached, in combination with heat or voltage applied. The rubber seals normally are quite robust, but they were widely damaged when the PCBA was cleaned after assembly with solvents. This is the reason for leaking capacitors in 1980s and 1990s equipment. The only way around this is to either periodically inspect the board for signs of leakage, or to replace them with new capacitors (and not repeat the damaging solvent cleaning).
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 04, 2018, 03:09:51 pm
CR contents are not solid, but they are not harsh alkali like alkaline cells. Specs mention lithium perchlorate dissolved in organic solvents. Lithium perchlorate salt is neutral (since it is a salt of a strong acid (perchloric acid) and a strong base (lithium hydroxide)).

Electrolytic capacitors leak when their rubber seal (the bung) is breached, in combination with heat or voltage applied. The rubber seals normally are quite robust, but they were widely damaged when the PCBA was cleaned after assembly with solvents. This is the reason for leaking capacitors in 1980s and 1990s equipment. The only way around this is to either periodically inspect the board for signs of leakage, or to replace them with new capacitors (and not repeat the damaging solvent cleaning).

Thank you. So, if I don't use the cartridge (I don't need to use it because I've already done a backup) and I preserve from charges and high temperatures (like using a ESD bag + control the temperature) the risk is really low. Those capacitors (from the photo) seems to be in very good conditions, there shouldn't be visible damages
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 04, 2018, 03:13:41 pm
Hi Doctorkong,
          I own quite a few old cartridges for several systems (although I wouldn't describe myself as a collector). Static damage would be an extremely unlikely event with these cartridges as the contacts are well protected from finger touching etc. The only time I've ever seen one being damaged was during connection/disconnection from the console, at which time you'll have removed the anti-static bag anyway. If they are in a box and not being handled, there is zero chance of them being damaged from static. The biggest longterm risk to these "newer" cartridges (the older ones only contained a single EPROM) are the electrolytic capacitors which can leak and eat away at the copper tracks.

McBryce.

Happy to know another cartridge owner! :) What do you do when you remove cartirdges from the console? Do you use some precautions?
Title: Re: How should I protect from electrostatic charges?
Post by: Docara on July 04, 2018, 04:25:59 pm
Hi Welcome to the forum.

I've been to Italy and know what your power grid is like (if you can call it a grid   :palm:  |O) I would suggest either an online or line-interactive UPS. You guys can have horrendous spikes going through the mains just before your power cuts off.

At least having something like this it should protect those old capacitors.

Hope this help
Matt
Title: Re: How should I protect from electrostatic charges?
Post by: JS on July 04, 2018, 08:41:01 pm
Then you could use some conformal coating around the caps, I use a spray can insulator to protect traces en rough environments, so if they leak the electrolyte won't get in contact with the PCB.

JS

Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 04, 2018, 11:22:52 pm
Thank you. It's so beautiful to know something more about electronics from exopert like you. It's a world I don't know that I would like to explore better but I need the right people to help me.
What's the reason why a CR battery, covered by a plastic shell like that one, can drain its power if the cartridge is closed in an ESD bag? The batter is not in contact with the bag. Maybe the position is risky?
I'm asking because I don't understand the physics behind it.
Title: Re: How should I protect from electrostatic charges?
Post by: helius on July 05, 2018, 12:04:00 am
What's the reason why a CR battery, covered by a plastic shell like that one, can drain its power if the cartridge is closed in an ESD bag?
All types of cell have some level of self-discharge (https://en.wikipedia.org/wiki/Self-discharge), even if they are still sealed in their original packaging. The chemical energy is slowly wasted in side reactions that do not produce an external current. The exception is if some of the chemicals are left out, for example, a lead-acid battery shipped dry to the user, or a zinc-air cell with a sticker sealing the air holes.
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 05, 2018, 12:24:10 am
What's the reason why a CR battery, covered by a plastic shell like that one, can drain its power if the cartridge is closed in an ESD bag?
All types of cell have some level of self-discharge (https://en.wikipedia.org/wiki/Self-discharge), even if they are still sealed in their original packaging. The chemical energy is slowly wasted in side reactions that do not produce an external current. The exception is if some of the chemicals are left out, for example, a lead-acid battery shipped dry to the user, or a zinc-air cell with a sticker sealing the air holes.

Ok I got it. My question is: why does the ESD bag can accelerate the process of draining energy?
Title: Re: How should I protect from electrostatic charges?
Post by: JS on July 05, 2018, 04:02:22 am
Resistive material, resistive absorbes energy and turn it into heat, high resistivity limits the current so it can damage anything.

Let's say your part inside the bag is charged with 10kV respect to you, like the plates of a cap, then it conducts slowly dissipating that energy, so for the time you are taking the part out of the bag it's at the same potential you are. If you are grounded to start with as all your equipment and desk there is no more charge to damage anything.

Anti static bags have a inner conductive layer so external spikes can't penetrate and damage parts, if only a high resistivity layer is present like in static dissipative bags external charges can penetrate directly into the part and damage it anyway. Dave has a video demostrating this with a ESD gun, frying components in pink bags while the ones in the grey bags suevive without much trouble.

JS

Title: Re: How should I protect from electrostatic charges?
Post by: McBryce on July 05, 2018, 07:35:12 am
Hi Doctorkong,
          I own quite a few old cartridges for several systems (although I wouldn't describe myself as a collector). Static damage would be an extremely unlikely event with these cartridges as the contacts are well protected from finger touching etc. The only time I've ever seen one being damaged was during connection/disconnection from the console, at which time you'll have removed the anti-static bag anyway. If they are in a box and not being handled, there is zero chance of them being damaged from static. The biggest longterm risk to these "newer" cartridges (the older ones only contained a single EPROM) are the electrolytic capacitors which can leak and eat away at the copper tracks.

McBryce.

Happy to know another cartridge owner! :) What do you do when you remove cartirdges from the console? Do you use some precautions?

I chuck them unceremoniously into a metal drawer under the table. The cartridges I have are from (sorted by age):

Atari 2600
Commodore 64
Atari XL/XE
MSX
Amstrad CPC+
Gameboy
Gamegear

Nothing rare or valuable though. I've only ever had one cartridge that failed which was for the Atari XL/XE and it seems to be corrupted data in a OTP ROM. The IC was still readable, so static is unlikely to have been the cause.

McBryce.
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 05, 2018, 12:15:38 pm
Resistive material, resistive absorbes energy and turn it into heat, high resistivity limits the current so it can damage anything.

Let's say your part inside the bag is charged with 10kV respect to you, like the plates of a cap, then it conducts slowly dissipating that energy, so for the time you are taking the part out of the bag it's at the same potential you are. If you are grounded to start with as all your equipment and desk there is no more charge to damage anything.

Anti static bags have a inner conductive layer so external spikes can't penetrate and damage parts, if only a high resistivity layer is present like in static dissipative bags external charges can penetrate directly into the part and damage it anyway. Dave has a video demostrating this with a ESD gun, frying components in pink bags while the ones in the grey bags suevive without much trouble.

JS

Ok, got it. But if the bag isn't in direct contact with the battery, how can the battery be drained? From what I know low voltages need to be in contact to another conductive material to generate the flux of electrons (so electricity). Sorry for all of these questions but since I know just a few physics is interesting to know more about.
Title: Re: How should I protect from electrostatic charges?
Post by: JS on July 05, 2018, 12:19:20 pm
Draining the battery wasn't the bag alone, but protdcting the fingers shorting them, discarded that idea battery behaves as designed.

JS

Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 05, 2018, 11:12:13 pm
Draining the battery wasn't the bag alone, but protdcting the fingers shorting them, discarded that idea battery behaves as designed.

JS

I'm sorry. I tried to understand what it means but I couldn't understand what you said :(
Title: Re: How should I protect from electrostatic charges?
Post by: JS on July 06, 2018, 01:02:54 am
With the anti-ESD bags there is no problem, if you add something conductive touching the fingers you could drain the battery, as someone said the fingers are protected already as they are designed as a outside world interface, you only need the whole thing to not be at 20kV when you first touch it. Bag is enough, no problems, not drained battery.

JS
Title: Re: How should I protect from electrostatic charges?
Post by: Doctorkong on July 06, 2018, 11:03:58 am
With the anti-ESD bags there is no problem, if you add something conductive touching the fingers you could drain the battery, as someone said the fingers are protected already as they are designed as a outside world interface, you only need the whole thing to not be at 20kV when you first touch it. Bag is enough, no problems, not drained battery.

JS

Thank you, you were very gentle, like all the people here. I found a very great community.
So, if I use the ESD bag I should just check leaking from capacitors during the years and my cartridge is safe. Right?