CPS1 deep cleaning

Hello everybody
I wanted to know if I clean my cps1 boards (no battery ) correctly.

I just removed all Eproms , washed the boards carefully under water and a small soft brush. After I rinsed them with isopropyl alcohol, quick dry with hair drier (soft and no hot air) and let them dry for two days to be sure no humidity remains on any pin.

It worked perfectly for my SF2' board but will wash more rare boards that I own. Is it the right way to do it ?

Sounds good to me. Just make sure you are careful when pulling and inserting chips.

Do you do anything to clean the chips themselves?

No.

Unless your board has shit spilled on it or already doesn't work making it look mint always carries a minor risk. You need to dry them properly or water ingress may happen. Meme all you want but the fault won't show up until years down the line, potentially long after you don't have the board.

Here is a good quote from brizzo on Arcade Projects if you do need to wash one though.

Bake your cleaned PCB in the oven for 2 hours @ 175F. Turn off oven and allow to cool without opening.

It is not actually possible to properly dry a populated PCB using compressed air, fan, or sitting in the sun. Water will absolutely ingress into chip packages, it has to be baked out or it will long term damage components.

But I do approve of simple green, that is my go to for filthy boards.


It is best to only wash a PCB if it really needs it, like years of caked of grime when compressed air and a soft brush cannot get it mostly clean.

Like monitor chassis grime, animal liquids, nicotone+dust, etc. Don't wash boards if they have just a bit of dust on them.

Click to expand...

This is true. I have heard a number of times to bake in oven at low. Full agreement with this.

I've never cleaned a board as of yet. Some dirt is not going to pose a problem to the board itself. If someone were to spill soda or juice on it... Yah, needs a cleaning.

I’ve low temp baked boards after cleaning (Windy II controller I/O, yaton MVS jawns); no harm done.

Thank you people for all your advices.
In the past I used really thin sand paper to remove corrosion on the chips really gently but I don't anymore.
I will not even remove the chips, I agree with you ChuChu Flamingo, problems may appear over time and I really want to keep these boards forever ^^.
The boards are not dirty as hell so thinking that the best is a dry clean with Qtips and alcohol to take no risk.

It may be idiotic on my side but what will baking it to a temperature that is lower to the water evaporation rate do? I know it will help with humidity but for that "water ingressed into chip packages" shouldn't you be baking it over 100ºC?

I bet that going over that temp may cause condensers but...

I think that 100c is the boiling point of water, if you bake low temperature it may evaporate quicker I suppose

Hawwa said:

It may be idiotic on my side but what will baking it to a temperature that is lower to the water evaporation rate do? I know it will help with humidity but for that "water ingressed into chip packages" shouldn't you be baking it over 100ºC?

I bet that going over that temp may cause condensers but...

Click to expand...

175F seems to be the common number but ive seen it a tiny bit higher or lower. He probably keeps it below 85C as that is what most of these old capacitors are rated for iirc. You also don't want to burn any plastic. Channelmaniac stated out of the hundreds of boards he has washed that is the only issue he has encountered. Drooping mvs plastic near the memory slots.

The whole goal of this is to get the water to evaporate and not dry to prevent leaving remnants inside of your ics (like limestone, minerals, etc). These contaminants may or may not react with your ics down the road.

Ideally if you're to wash and then bake a PCB you would do it prior to immediately replacing the capacitors. They could do with a change by now anyway.

I would also use distilled water, not tap water.

If you need to remove rust from chip legs use a fiberglass pen works extremely well.

I just got some filthy PCBs in so maybe trying to clean them this way would be a good idea (complete with oven drying)

The way I do it is to wash the board with isopropyl alcohol and do a ultrasonic bath to neutralize the acid from the leaked electrolytic capacitors, in general we do this before a full board recap with Polymer Solid Aluminum Capacitors[1][2]. If I need to wash to board with water for some reason, I would use distilled water to avoid copper and other metals oxidation.

The thing about cooking the board, it is a required maintenance procedure to avoid PCB crack and delamination caused by moisture expansion (water) as described in the standard IPC/JEDEC-J-STD-033C[1]. This is also a required procedure to do on any fiberglass PCB before you do any selective soldering or desoldering[2][3]. Another thing about decade old boards it's that ceramic capacitors degrade/changes over time and to recover it, you have to preheat the board than apply 125 ºC on each and every ceramic capacitor on the board to heal it.
https://www.murata.com/support/faqs/products/capacitor/mlcc/char/0006

My advice to you, do not preheat the board if you don't know what you are doing, some people preheat the board to 100 ºC (212°F) but the electrolytic capacitors on the board are 85 ºC (185°F) types.