Later yesterday I managed to des-older/remove the old one and stick the new one on the board.
I kind of hoped it would start up when held near a light bulb but no joy.
I suspected it would need a good kick to get a completely discharged capacitor running though. Since I’m waiting for another couple of batteries – one is in the Vue and the VP2 ate the other one – I just left it in the window first thing.
It took until about 10:30 to start transmitting which was a surprise.
The test will be how long it runs after dark - I’ll leave it in sun all day.
Must say doing the soldering was not a whole lot of fun, the tricky part is getting enough of the old stuff removed to insert the pins of the new one.
I have a kit with a syringe thing to suck it out, first time I used it and I think it would have been all but impossible (for me) without it.
You seem to need three hands to do several things at once.
Actually inserting and soldering the new one was the easy bit - but I’m still concerned it might not have enough solder on.
Having another session at it while it is working could be like snatching defeat from the jaws of victory though!
At least it seem the part Maplins supplied is compatible.