The Repair Log

Moonboon Motor Repair

2025-12-10T00:00:00+00:00

In short: If your Moonboon motor was dropped and the knobs no longer work, the two potentiometers behind the knobs have probably shattered. They are cheap standard parts (P170S2-QC15BR1K</code>) and can be replaced with basic soldering skills. </blockquote>
My Moonboon baby hammock motor fell to the floor, and the control knobs stopped working. This turned out to be a fairly simple repair. From the way the motor is constructed, I suspect this is a common issue if the unit is dropped. If you have a similar motor and the knobs seem broken, this post is for you.
Before you start</h2> Soldering: This is a relatively simple repair, but it does require some basic soldering skills. If you're not comfortable soldering, you can still do most of the disassembly yourself and order the replacement parts. That way, it's much easier to ask a friend or an electronics repair shop to finish the job. Sourcing parts: You need two potentiometers, model number P170S2-QC15BR1K</code>. They are inexpensive and available from electronics distributors like DigiKey and Mouser. However, shipping can cost several times more than the parts themselves. Local makerspaces or electronics enthusiasts often place orders from these suppliers, so you might be able to join an existing order to save on shipping. Tools: Two spoons (or something similar) to pry off the knobs, side cutters, and a soldering iron. The repair</h2> To open the unit, the potentiometer knobs need to be removed. They are press-fit and can require some force. I used two spoons on either side to lever them off evenly. When removing the motor assembly from the shell, you'll need to take off the split ring for the rocking wire. Be careful, as the wire can retract into the motor. I attached the ring again like in the picture below to avoid this. Here you can see the shattered potentiometers. When desoldering, I cut the three middle legs of each potentiometer so I could remove them one at a time. The wires connected to the side lugs should not be removed from the PCB. Instead, carefully desolder them from the potentiometers, as we'll reuse them. After replacing the potentiometers, reassembly is straightforward. Follow the steps in reverse, and you should have your motor back in working order!



Fluke 115 Multimeter Repair
2025-11-17T00:00:00+00:00

In short:</strong> The display showed nearly the same garbage on every setting, and later the continuity buzzer was dead. The cause was corroded plated through-holes (vias) that broke two connections on the PCB. Both were fixed with solder and a small bodge wire.</p>
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This post is about repairing a Fluke 115 multimeter that had stopped working. As with many of my repairs, this was a device I bought broken and brought back to life. The fix turned out to be fairly simple, which made it a great deal - and meant I could finally replace my cheaper multimeter. The 115 isn't one of Fluke's top-tier models, but it's still a solid step up from what I had before.</p>
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When I first powered it on, the multimeter did react when turning the selector wheel, and the screen displayed something</em>, but it behaved very strangely. Most settings gave nearly the same output as in the picture above, and none of the functions worked as they should.</p>
Finding the fault</h2>
After opening the device and inspecting the PCB, I found the likely culprit. Several plated through-holes labeled as test points were damaged, with the copper completely gone. It looked a lot like acid damage, but oddly there were no signs of leakage from the battery, and these test points were nowhere near the battery compartment. After some probing with my (other) multimeter, I confirmed there was a break around TP10, where a trace connects to one of the damaged vias. On the opposite side of the board that same trace connects to one of the contact pads used by the selector wheel, making this a very plausible reason for the strange behavior.</p>
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Fixing it</h2>
To fix it, I scraped away the solder mask on the affected trace and added solder to reconnect it to the through-hole. Looking at the repair in hindsight, it's not the prettiest thing I've ever soldered - but the important part is that the trace is restored, both to the via and to the corresponding trace on the other side of the PCB.</p>
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After reassembling the multimeter, it powered on and most functions worked as expected. The only thing still broken was the continuity buzzer. So, back inside it went. After desoldering the buzzer, the problem was obvious: another damaged via with the copper plating missing, very similar to the first failure.</p>
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A small bodge wire bridging the broken connection fixed the issue, and the buzzer came back to life. With that, the multimeter was fully repaired - and since then, it has been hard at work helping me repair other electronics.</p>
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Repairing Water-Damaged Electronics
2025-11-16T00:00:00+00:00
General approach</h2>
Some people seem to think that water is the kryptonite of electronic devices - that once something gets wet, you might as well throw it away. In my experience, repairing water-damaged electronics is often quite simple. Most of the time it comes down to thorough cleaning.</p>
Substances like salt water, fizzy drinks, coffee, and detergent can be more troublesome, but the general repair approach is still the same.</p>
If you get your hands on a device that was recently exposed to water (or anything water-like), I recommend the following steps:</p>

Disconnect all power sources if possible - unplug it and remove any batteries. Don't try to turn it on "to see if it still works" - running current through a wet circuit is what causes the lasting damage.</li>
If the device was soaked in anything other than clean water, rinse it with clean water. Tap water is fine.</li>
Open the device to expose the circuit boards and dry them with a paper towel.</li>
Clean the electronics thoroughly with isopropyl alcohol (or similar). A small brush or cotton swab works well for this. For small circuit boards, I like completely soaking them in alcohol for a while.</li>
Let the device dry completely, then test it. If it doesn't work, repeat step 4 and try again.</li>
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There are several reasons a device may stop working after coming into contact with fluids. Two common ones are:</p>

The residue may be slightly conductive, creating unintended connections between components.</li>
Oxidation on contacts, such as those on inter-board connectors, can prevent proper electrical contact.</li>
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Fortunately, the remedy is usually the same: thorough cleaning. Oxidation can often be removed by rubbing the contacts with a cotton swab soaked in isopropyl alcohol. If that isn't enough, some very light sanding can help restore good conductivity. If you have it on hand, contact cleaner spray is also a good way to remove oxidation.</p>
Examples</h2>
Bathroom scale</h3>
At one point my bathroom flooded, and the bathroom scale took a hit. The picture below shows the main circuit board after the dirty water had dried. You can see residue and oxidation across much of the board. After a good cleaning with isopropyl alcohol, the scale worked perfectly again.</p>
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Car key</h3>
A family member forgot to empty their pockets before running the laundry, so their car key got the full 60° wash cycle - detergent and fabric softener included. When I received the key it had already dried, but after a proper rinse with isopropyl alcohol it worked fine again. After the first rinse the power consumption was still unusually high, but after a second, more thorough cleaning, it was as good as new.</p>
The buttons here are a good example of components that can be troublesome after fluid damage. There are mechanical contacts on the inside, and cleaning on the outside of the buttons is often not enough. In these cases I find that leaving the device soaked in alcohol helps displace whatever got inside the buttons. Again, here contact cleaner spray can be really helpful to remove the oxidation.</p>
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Power drill</h3>
While building a new pier, I managed to drop a DeWalt power drill into the sea. After retrieving it, I removed the battery and dunked the entire drill into a bucket of clean water for several hours to get the salt out. Afterwards I opened it up, cleaned all the electronics with isopropyl alcohol, and added a few drops of oil to the mechanical parts. The drill is still working fine today.</p>