Fixit Clinic 2024-04-06

This one was held in San Mateo Public Library.

First, I worked on a rice cooker whose non-rechargeable lithium battery had run out. From my understanding, the battery was used to avoid the need for an AC power supply, needed not only to keep the clock running when the appliance was unplugged, but also to operate the entire user interface. After disassembling the device, we replaced the battery by desoldering the old one and soldering the new one in.

It was pretty clear to me the battery was not meant to be replaced, which surprised me since the rice cooker was from Zojirushi, a rather premium brand. In addition to the fix requiring soldering, which is simply not accessible to many people, disassembly was somewhat challenging despite its simplicity. Although the battery is meant to last for the better part of a decade, about the life of the appliance, I don’t see why they couldn’t have included the exact same coin cell in a battery holder rather than soldered in for a few cents more. (Side note: The client was a White fellow, so I suspect the rice cooker was not frequently used and the battery ran out before wear-and-tear killed the appliance.)

Next, I worked on an expensive Italian halogen desk lamp with a small toggle switch that wasn’t working reliably. Although the overall design seemed pretty robust and repair-able, we weren’t able to access the switch located in the head assembly. I recommended that the owner seek a replacement assembly online, which was available for around $70 against the lamp’s original cost of $400.

After that, I tried to fix a “LED Night Light 3-in-1 Motion Sensor Night Light Plug in, Rechargeable Flashlight, Emergency Night Light for Bedroom, Bathroom, Living Room, Stairways, Hallways – Cool White” that wasn’t turning on. (If you can’t tell from the Amazon product name, it’s a nightlight that’s wirelessly charged from a plug-in wall holder and can be removed and used as a portable flashlight.) We first suspected a dead battery, not uncommon in this sort of device, but determined that it was functional after briefly charging it with a DC power supply. Then we opened the wall holder and found a puffed 250 V 8.7 μF electrolytic capacitor, which unfortunately nobody had on hand.

Finally, I fixed a vibrating “fascia roller” which stopped functioning after being dropped. It was basically a vibrating wooden stick about 500 mm long that you rub around your body to release tension in your muscles. Anyhow, after disassembling it, we found it contained a rechargeable 18650 lithium-ion battery that was soldered to a circuit board. One of the solder tabs had been snapped from the impact of dropping the device, and the user suggested we use foil tape to reattach it. Since there was none on hand (and also since the adhesive on foil tape is non-conductive), I snapped off one of the solder tabs from the dead rice cooker battery and used it to replace the broken tab.

This device was definitely made to be fixed. Disassembly was simple: we only had to twist off a plastic cap, then undo four screws to access the circuit board. Then, the entire circuit board assembly could be very easily removed — the action of pulling it out disconnected a barrel jack, with no need to fuss with wires.