With my 7300 now over 2 years old the internal battery was well and truly knackered, failing to keep the clock powered for more than a few minutes off the power supply. Time to put on my Big Girl Pants and dig out that soldering iron.

Turns out it wasn’t all that difficult, with the trickiest part being the removal of the old cell. My initial approach was to use my hot air gun with its finest nozzle but I was put off by the proximity of some very small SMD components, which would no doubt disappear into the darkest corner of the shack. Instead I chose a fine tip and applied the soldering iron to the rightmost (positive) tab first, gently teasing it upward as soon as I was sure it was moving independently from the track. There was enough flex in the material to bend it slightly upward and keep it off the PCB while I heated the leftmost (negative) tab, which took ages even with a slightly larger tip and the iron set to 450℃. Guess those needle nose pliers are quite a good heatsink after all. The one thing I would stress at this point is that those tracks are real easy to lift, so it’s important to take plenty of time and heat.

My chosen replacement cell was the ML1220 which is slightly larger and should last a long time before it needs to be swapped out. To make subsequent replacement easier I fitted some fly leads before wrapping it in elastic tubing and fixing it to the radio’s chassis using a 3M sticky pad. From start to finish the job took around 40 minutes and two cups of coffee, replacement parts under £5.