Fixing stuff: Mr. Coffee and Nerf Stryfe dart gun

Recently I had occasion to fix a couple things: Our Mr. Coffee coffeemaker and Joseph’s Nerf Stryfe dart gun.

Mr. Coffee

Our Mr. Coffee coffeemaker had become very, very slow to brew a pot of coffee. We tried cleaning it with vinegar, thinking maybe something was clogging a hose, but that wasn’t good enough.

I found a coffee bean had become stuck in the ascending water tube and was blocking a little check valve. But as soon as I tried to remove the bean, I busted the hose.

The coffeemaker with the new hose.

I disassembled the coffeemaker and removed the two hoses. I inspected each hose as well as the heating pipe, and found that a coffee bean had become stuck inside the ascending water tube and was blocking a tiny check valve. I tried to squeeze the bean out of the hose, but ended up splitting the hose.

I set aside the check valve and all the screws and pieces. Then I ordered some 9m x 13mm food-grade clear silicone tubing from Amazon. It took more than a week to arrive. Once it did, I cut a length of tubing, inserted the check valve into the tube, then re-assembled the machine. It worked perfectly!

Nerf Stryfe

Joseph’s Nerf Stryfe dart gun had stopped working. At first we thought it just needed fresh batteries, but changing batteries made no difference. Next I took it apart to look for mechanical problems, but I didn’t find any. Clearly it was an electrical issue, but at first I wasn’t feeling up to figuring it out. After a week or two, I did some reading and decided to give it a try.

Overview of the switches inside the Stryfe

I guessed the problem was likely to be one of the switches. There are multiple switches inside the Stryfe. One of them is an actual trigger, but the others are meant to disable the motors in certain circumstances. The top switch turns off the motor if the jam door is open. The center switch turns off the motor if there is no magazine inserted into the dart gun. There is also a thermistor which turns off the motor after it gets hot from a certain amount of electricity flowing through it.

I got out my multimeter and checked the magazine and motor trigger switches first. They each have only two terminals, so it was simple to do a continuity test. They looked fine. I tested the thermistor, and it also seemed fine.

I had to do a little more research on the jam door switch, because it had three terminals, and I wasn’t sure which ones should show continuity. Someone on Reddit explained that there should be continuity between the middle (red wire) and right (orange) when the switch is pressed. There wasn’t, which meant the switch had gone bad.

My solution was to solder a jumper between red and orange. This bypasses the switch altogether, so the motor will continue running even if the jam door is opened. For really little kids that might not be a great idea, but for Joseph it should be fine.

Any way, the gun works again, and Joseph is happy.

Closeup of the jam door switch after I soldered a jumper between the red and orange wires.

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