My parents Macbook Pro A1502 recently developed some heavy screen glitching / colorful flickering all over. Here’s what I...

It’s more of a hack/workaround than a fix but costs 1% of a display and doesn’t even require tools: I ended up getting one of these $5 virtual HDMI dummy plugs that we now just keep attached to the Macbook permanently. This 100% solved my flickering problem and the machine is perfectly usable again.

If the red light appears on the top of the toothbrush, you might have a slightly different model with a pressure sensor LED. See here: Is the Pressure Sensor Broken?

#1 If this only happens when the toothbrush is on, the pressure sensor plate doesn’t get a connection. It’s a a little metal spring with two contacts pressing against the motor housing and the contact opens if too much pressure is applied. Try cleaning these contacts and the opposing area if they still visibly connect. If they are bent, you might have to take apart the whole thing to straighten them. #2 I had a similar problem where the red light came on even with the toothbrush off, completely draining the battery over night. Opening it up, it seemed that the metal spring created a short between the upper frame and the battery. Wrapping the spring in some duct tape seems to have fixed that issue. Update on the “red/green light of death“:: After the problem came back for me after a while, I took a closer look at the toothbrush. The reason for the LED lighting up is actually a short between the metal cage and the feed wires for the LED. These were bent into the direction of the cage in my case. Bending the...

If you need to transfer the rubber spacers to the plastic frame of the new battery (because you got a cheap one that didn't come with any), take note that they come in 2 slightly different heights.

The shorter ones go towards the front edge, the higher ones to the center of the MacBook.

You can remove them by pushing them through from the bottom of the old frame with your screwdriver. Getting them into the new battery frame requires some fiddling. Try to push them in from the top while trying to get the wide part through the hole with a toothpick.