Comment by jacquesm

No, this was a couple of decades ago, I didn't have a blog back then and I have zero evidence. But I can tell you some of the details: the device was a Philips 'Marc' CB transceiver. They made only one model both for the US and the EU market so there were 22 channels available in the EU and 40 iirc in the United States. But the rotary channel selector did have all 40 positions. That made me wonder... what if? So I opened the device and there was this very large plastic blob in the middle of the circuit board with obviously a large (40 pin iirc) chip underneath it. I realized that if I tried to physically remove the blob that I would most likely break the chip so that wasn't going to work.

But it was clear what it did: as soon as the channel selector went to a forbidden channel the blob sprung into action to disable the chip underneath. I measured the effect on the pins underneath that were accessible from the other side of the board and noticed that a whole bunch of them got shorted to ground. That was the hint I needed. A friend ran a laser game company and they had a nice little IR camera with built in display, that was used for calibration of the IR beam collimators in the laser guns (the laser doesn't actually do any of the shooting, the thing is basically just a very powerful remote control with a lens that sends out a relatively narrow beam). I set it up above the the blob and set the channel selector to a good channel and let it warm up. Had a look with the camera. Then set the channel selector to a bad channel, let it warm up again and had another look with the camera. The difference was pretty obvious, there was a hotspot right in the middle of the blob. I marked the spot and made a drill jig, then it took me a few days to gather courage and stick the drill in, it worked on the first try. That gave 18 nearly empty channels to play with. Once I had it figured out the second one was a lot easier :)