• Hello, Guest! Welcome back, and be sure to check out this post for more info about the recent service interruption and migration.

OK to put an SE/30 power supply PCB in ultrasonic cleaner?

captainserial

Active member
I just finished recapping the analog board and power supply in an SE/30. I have put many PCB in my ultrasonic cleaner with no issue, but this Sony power supply has some components on it that look like they might not like the ultrasonic bath, like whatever this one that looks like a roll of tape is.

The board is filthy with capacitor juice residue, and I would rather not clean it with 500 Q-tips.

Has anyone here ever put a power supply PCB in an ultrasnoic cleaner? Is it safe?
 

davidg5678

Well-known member
I think the majority of the PSU components should be okay in the ultrasonic bath --it's a bit tricky to find quality ultrasonic cleaning information online, as unfortunately, most of it is junk. From what I've read, the main concern is damaging delicate MEMs components on much more modern PCBs (like on an iPhone logic board). The component that looks like a roll of tape is an electrical transformer, and it may not like getting wet. Something I've seen people say about ultrasonic cleaners is that if you shake anything hard enough for a long time, it will eventually break or degrade.

I wouldn't clean the PCB for longer than a minute or two, as you'll risk damaging things the longer you run the machine, but it is probably fine for a short time. What kind of cleaning product are you adding to the water? I have had good results with a chemical called Branson EC mixed with distilled water.

After you clean the PCB, you'll need to make sure it is completely dry before applying AC power, as residual moisture could be really risky to have around in this case. I think if you stick the PCB in the oven at a low temperature (nothing near hot enough to melt plastic) for a while, the water should all evaporate.

As an alternative (and less risky) solution, you could purchase enough isopropyl alcohol to give the entire PCB a bath. The isopropanol should dissolve the flux residue fairly well. A toothbrush works well to agitate the flux, and paper towels would absorb most of the isopropyl alcohol after you pull the board from the liquid. I think that this technique should be much faster than swabbing the entire board with Q-tips.
 

aeberbach

Well-known member
I would not want to submerge a transformer into an ultrasonic bath. It may never correctly dry. Just too many layers and gaps for liquid to sit.
 

captainserial

Active member
I think the majority of the PSU components should be okay in the ultrasonic bath --it's a bit tricky to find quality ultrasonic cleaning information online, as unfortunately, most of it is junk. From what I've read, the main concern is damaging delicate MEMs components on much more modern PCBs (like on an iPhone logic board). The component that looks like a roll of tape is an electrical transformer, and it may not like getting wet. Something I've seen people say about ultrasonic cleaners is that if you shake anything hard enough for a long time, it will eventually break or degrade.

I wouldn't clean the PCB for longer than a minute or two, as you'll risk damaging things the longer you run the machine, but it is probably fine for a short time. What kind of cleaning product are you adding to the water? I have had good results with a chemical called Branson EC mixed with distilled water.

After you clean the PCB, you'll need to make sure it is completely dry before applying AC power, as residual moisture could be really risky to have around in this case. I think if you stick the PCB in the oven at a low temperature (nothing near hot enough to melt plastic) for a while, the water should all evaporate.

As an alternative (and less risky) solution, you could purchase enough isopropyl alcohol to give the entire PCB a bath. The isopropanol should dissolve the flux residue fairly well. A toothbrush works well to agitate the flux, and paper towels would absorb most of the isopropyl alcohol after you pull the board from the liquid. I think that this technique should be much faster than swabbing the entire board with Q-tips.
I’m using SRA TruPower #35 and distilled water, usually at 50C for 5 minutes per side. I have plenty of IPA so I am probably going to carefully wash just the board with that.
 

captainserial

Active member
I would not want to submerge a transformer into an ultrasonic bath. It may never correctly dry. Just too many layers and gaps for liquid to sit.
That’s exactly what I thought when I looked at it. I’m going to use IPA on just the board. I was worried because literally the entire top of the board was covered with capacitor liquid, and I wanted to make sure I got all of it.
 

joshc

Well-known member
I wouldn't advise this either - lots of sensitive components on a PSU that you don't want to soak. A light IPA swab will be enough to get it clean.
 

cbmeeks

Well-known member
Don’t take this as advice, but I have taken old PSU’s from PC’s (AT and ATX) and have literally hosed them with the water hose. The VERY dirty ones. I did the same thing with an old Mac PSU too. Just made sure they were bone dry before testing them.

It helps that summers are brutal here and things dry fast outside. Lol.

Oh, these were all switching power supplies. Soaking paper wrapped transformers may not be a great idea.
 

bdurbrow

Well-known member
Hmm... just a random thought - how about sticking them in a vacuum chamber before the electrolytics are put back on? You can get reasonably large ones on eBay, so.... ???
 
Top