Best ways to clean an edge connector that is PCB mounted

[Game-Tech.us]

I work on a lot of older video game consoles and am constantly cleaning edge connectors that the game cartridge pcbs push in to. A good cleaning has saved more vintage consoles than I can remember even after 20 plus years of use and abuse.
My process was to apply formula 409 over some sort of substitute board usually covered with a cloth and insert/remove repeatedly to scrub the contacts until a fair amount of bubbles form then let it dry a bit and retest a game. I soon discovered the 409 was leaving a film on the contacts after it dried and games would have trouble loading. So I then started to use another substitute board (this one is pressed felt) soaked in %99 propyl alcohol to rinse off the 409. This works perfect, but then as the felt board started to fail to stay rigid, I thought why not use electronic contact cleaner to spray out the connector. I do not need to scrub it again with the alcohol just rinse out the 409 residue before it dries. This also works perfect, BUT its too expensive to keep using. My next experiment will be to fill a sure shot sprayer with the %99 rubbing alcohol, pressurize it, and use this instead of the contact cleaner. It should work just as well and I won't have to pump a regular spray bottle and may have more control over pressure and spray pattern.
Just wondering if any one else has ideas or experience with such matters.

 

[KeepItSimpleStupid]

Yep, I have lots of experience with films of chemicals. When I was doing some semiconductor fab/measurements, I had trouble with methanol films and even wax like films. These were measureable in the pic-amp range, but it was a problem for me.

The standard method was: trichlorofloretelene, methanol followed by a liquid freon solvent and dried immediately by an inert gas gun. The Freon step can be replaced with a citrus based cleaner such as: https://ca.mouser.com/Search/ProductDetail.aspx?qs=ItEYEd4DnG0W7Th6Yf8eyQ== If this doesn;t work search for "citrus base cleaner".

It's very important to actively dry the citrus. Air gun etc.

Note that there are specialty chemical for cleaning contacts and gold contact fingers: **broken link removed**

Stabalent 22 is really good: https://www.posthorn.com/Stab_2.html to use when your all finished.

Re-inserting of edge connectors is liek the first thing to do. Inspect the fingers for damage and watch out for dissimilar metals.

 

[KJ6EAD]

I usually clean such things with:
1. Compressed air, brush and vacuum to remove loose debris and dust.
2. Water-based detergent and brush to remove sugary residue (dried soda, etc.) and stuck on crud.
3. Water jet rinse from a squeeze bottle to remove emulsified crud and detergent.
4. Alcohol rinse from a squeeze bottle to remove the water.
5. Compressed air to dry the alcohol.
6. A light film of contact lube, the kind that smells like fuel oil.

 

[Game-Tech.us]

KISS,
The point was to reduce steps or cost, not increase both, but I do get why you have to go to all that trouble some times, just not what i'm after.
I want to get away from expensive cans of contact cleaner and spray alcohol under pressure, do you think that will work?
Now if the person that buys the console wants to take it to the max i'll know what to tell him, heh.
Also don't have to worry about dissimilar metals, most all contacts are gold plated.

 

[Game-Tech.us]

KJ, do you use cans of compressed air or an air compressor.
If compressor, shouldn't we worry about oil and water and static electricity?
Does the alcohol really need to be blown off? Won't it evaporate on its own just fine?

 

[Game-Tech.us]

I've also heard of a few ppl putting entire PCBs into the dishwasher for cleaning off flux residue, any objections to that!?!?

 

[Game-Tech.us]

Oh, forgot one step. When using the cans of contact cleaner I was having major issues with condensation. I'm in illinois and its been high humidity here and the cleaner evaporates so fast it cools the PCB so much it starts sweating immediately. So I started putting the PCBs in front of a portable electric heater with a fan to dry them off, crazy...
Another reason I want to switch to pressurized can of %99 rubbing alcohol.

 

[KJ6EAD]

KJ, do you use cans of compressed air or an air compressor.
If compressor, shouldn't we worry about oil and water and static electricity?

I use both but prefer the shop air supply since it's stronger and cheaper. The air supply is clean and dry and I have an antistatic air gun.

Does the alcohol really need to be blown off? Won't it evaporate on its own just fine?

It will dry on it's own but takes longer and leaves a trace of residue.

 

[KJ6EAD]

I've also heard of a few ppl putting entire PCBs into the dishwasher for cleaning off flux residue, any objections to that!?!?

That method is best used in production or repair situations where the washability of all components and the composition of the flux is known. You create more problems than it's worth if you start damaging components.

 

[cr0sh]

Oh, forgot one step. When using the cans of contact cleaner I was having major issues with condensation. I'm in illinois and its been high humidity here and the cleaner evaporates so fast it cools the PCB so much it starts sweating immediately. So I started putting the PCBs in front of a portable electric heater with a fan to dry them off, crazy...
Another reason I want to switch to pressurized can of %99 rubbing alcohol.

Not sure if this would work, but MG Chemicals shows that the greater percentage of their "Super Contact Cleaner" is "Mineral Spirits" - you can buy plain mineral spirits from a hardware store, and it is probably much cheaper than buying contact cleaner. However, I don't know what straight spirits would do, or what you could mix with them to "thin" them out (perhaps methanol?). It might be worth testing out, though...

 

[hdc090360]

You might want to try buying your isopropyl in bulk. Go to a chemical supplier or factory that makes it and buy it direct from them. I used to buy it from a chemist to clean tape heads and it cost $7 for 300ml. I then found I could buy 4 litres from a chemical supply house for $20. This was several years ago so I can't tell you the prices now but the savings should still be relatively the same.