Argh, what have I done. Water on power supply of La Marzocco GS3

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by Icesheet »

My machine is going into storage as I'm moving house, so I was attempting to drain the boilers before I moved. I placed a plastic tube over the ball valve opened it and had my daughter direct the tube into the drip tray and I went round the other side to tip the machine. Unfortunately, at some point the tube came loose and water started leaking down through the power supply unit :(

I'm not sure how much but judging by the puddle on the floor enough to do damage. Some drips were leaking out the power switch anyway. Feel so daft now not just taking a few extra minutes to remove it!

What should my next step be? Give it time to dry and try and power it up, or get it sent straight away for a check up? Anyone else done this as well?

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#2: Post by Peppersass »

Water dripping from the power switch could certainly indicate that water has entered the brain box and likely gotten onto the logic board. But it's also possible that the water dripped down from the top of the brain box and hasn't gotten inside.

I wouldn't recommend just waiting for the machine to dry out and powering it up. There could be a lot of water in the brain box, which will take a long time to evaporate. Water on the logic board could cause a short circuit. Further, evaporated water may leave mineral deposits on the logic board that could cause a short circuit.

What to do depends on how comfortable you are with DIY maintenance. What needs to be done is an inspection inside the brain box and, if necessary, removal of all water and mineral deposits. If water is inside the box, it's a good bet that the logic board has gotten wet, so it'll have to be removed, cleaned and dried, which involves unplugging all the cables going to it, labeling them, and plugging them back in when done. The good news is that full recovery is likely as long as all traces of water and minerals are removed, the cables are reinstalled correctly, and no cables are pinched during reassembly.

If the thought of doing this work gives you nightmares, you should get an LM-qualified technician to do it. If you don't live near an LM service location that can send a technician to your old house, or it can't be done before/after you move, you'll have to send it in for inspection and cleanup.

If you're game, the job isn't all that difficult:

1. Remove the side covers, cup tray and top cover.
2. Unscrew the two screws at the bottom of the rear panel and lift it up to remove it.
3. Gently pull the plastic brain box out. There are a lot of cables running into it, so don't yank it or pull it out too far.
4. You should be able to get the brain box out far enough to access the five screws that hold the cover on. Removed them.
5. Lift the cover and take a photo of the wires at the back of the power switch so you know where to reconnect them.
6. Unplug the spade connectors at the back of the power switch. This will allow you to remove the cover.
7. Thoroughly inspect the interior, looking for signs of water or mineral deposits.
8. As water could be under the logic board and not visible, it must be removed for inspection and cleaning if needed.
9. Take a photo of the logic board, label all wires and cables connected to it, and disconnect the cables.
10. Unscrew the logic board and remove it.
11. Dry any water in the box and remove any mineral deposits with isopropyl alcohol (aka IPA, 99% or 91% preferred.)
12. Carefully dry the logic board and check for any mineral deposits. Clean off any you see with IPA and let dry.
13. You can dry the logic board with a hair dryer, but not too close to the board. You don't want to desolder any components.
14. Reinstall the board, plug in the cables, triple check the photo and labels to make sure all cables are in the right place.
15. Double check that the two ribbon-cable connectors are fully seated. They have a tendency to pull out when you reinstall the box.
14. Re-plug the spade connectors into the power switch using the photo from step 5.
15. Reassemble the cover. Install the cover screws. Make sure no cables are pinched under the cover.
16. Gently push the brain box back into the chassis. Don't yank or tug any cables, especially the ribbon cables.
17. Reinstall the back cover and install the two screws that hold it and the brain box in place.
18. Reinstall the top cover, cup tray and side covers.
19. Turn on the machine.

If you see anything strange with the display, or it doesn't come on, or if the buttons don't work, turn off the machine. It's likely one or both of the two ribbon cable connectors wasn't seated on the logic board or got pulled off when you pushed the box back in. If so, you'll have to go back into the brain box and reconnect them. If after doing that you still see odd behavior, immediately turn off the machine. Could be that there's still contamination on the logic board or it was damaged by the earlier leak.

Hope this helps.
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Icesheet (original poster)

#3: Post by Icesheet (original poster) »


Thanks, this was a very comprehensive and easy to follow response. Very much appreciated.

I have just finished following your step by step guide and it didn't go exactly to plan. When I opened the brain box there was some water but none of it seemed to have gotten on the logic board and there wasn't as much as I expected. Everything was fine up until the step of removing the logic board. There were 4 screws that I could see. When I removed them the logic board did not budge. It seemed to be glued in place. I tried to see if I missed any screws but I couldn't see any. I didn't want to risk doing any more damage so I gently soaked up the little water I could see and went over everything with a hair dryer on low heat. As far as I could see there was no liquid left. Of course I'm not sure if there is/ was anything under the logic board.

I re-assembled and briefly turned the machine on. Everything powered up on and I could hear the steam boiler starting to fill. It's late here so I just turned it off.

Do you think it's safe to start tomorrow or do you think under the logic board needs investigated? I may just see if I can get a technician to look at it anyway.

Thanks (not for the first time!) for your support!

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#4: Post by Randy G. »

I speak here while not knowing the machine specifically... Was the machine unplugged from the outlet when it happened? That is, was power cut off to the area which got wet? If so, I would not worry. Salt water sailing deals with this sort of thing with gear like handheld GPS and 2-way radios and such. They take the electronic gear which got wet and take out the batteries, wash it in clean water, dry the best they can and then put it in the oven with just the pilot light on and/or in a bag of plain white rice or special drying products like those which come in the little packets in shipped products.
When I overhaul a very used Hottop I wash the main circuit board with a toothbrush and a diluted grease cutting agent (like Simple Green for aircraft), rinse with clean water from a hand spray bottle, and blow off with compressed air. A quick spray with DeoxIT-D afterwards and they are fine. Unsealed mechanical switches, open relays, and electrical plugs and sockets all benefit greatly from DeoxIT.
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Icesheet (original poster)

#5: Post by Icesheet (original poster) »

Yes, the machine was unplugged and off. Good to hear that these components are more robust than I would have thought. I've let the machine get up to temperature and gave it a clean and backflush. No apparent issues, although I'll monitor it over time. Have contacted a company to se of they can service it for me.

As an aside, and not to absolve me of blame, I'm surprised the manual doesn't highlight this as a possible risk or advise to remove the brain box from its housing.

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#6: Post by Peppersass »

Strange. I've not heard any reports of the logic board being glued in place. I've pulled mine out of the machine many times. Could be a practice with new machines, but I can't imagine why LM would do that. What's the serial number on build date of your machine? They're on a metal plate attached to the front of the left side of the chassis. Did you buy the machine new or used? If used, it's possible that the previous owner glued the board in place (again, I can't imagine why) or conformally coated it (a method to prevent water damage) and put it in place before the coating dried.

I suggest you call LM for support. Tell them what happened and ask if the logic board in your vintage machine has been glued down.

There are only four screw mounts in the brain box I bought a few years ago. They have raised centers, so it's possible they've wedged into the holes in the logic board. If so, a somewhat stronger tug will be necessary to pull out the board.

Unfortunately, water has a tendency to get under the board. I've had a few incidents with water in the brain box, and though I didn't see any water on top of the board, there was water underneath. On more recent versions of the box, LM drilled some holes under the logic board, which helps but isn't 100% effective at preventing water contacting the board.

If water contacted the board, I'm sure it's better that the machine was off. However, that doesn't prevent dried mineral deposits from causing a short when the machine is powered up again.

Drying the board isn't sufficient. It has to be inspected and any mineral deposits cleaned off with IPA. The fact that the machine comes up without incident is encouraging, but it's no guarantee that the board hasn't been contaminated with mineral deposits and will start behaving strangely in the future. My machine worked fine most of the time for a couple of years, even though water was leaking from the boiler seals into the brain box. It would do strange things every now and them, until the damage got bad enough to make the logic board stop working altogether and require replacement.

I would certainly have a technician inspect both sides of the board.