The clock stopped towards the end of January 2017, and in spite of my efforts, it continued to stop daily for the next ten days, until I found the fault. I thought that the Broadsheet readers might be interested in the reason.
When it first stopped. I went and pushed the pendulum so that it was swinging, but the clock did not go, because the gear train was jammed somewhere. As soon as I pushed any gear wheel it released it, and the clock started to tick. It would go for about a day and then stop again, always at a different time. Every day I went and restarted it, each time trying to find where the friction was, but without success. It would stop the next day. I tried turning the gear train backwards after it had released but there was no friction at all at the time that it had stopped. Eventually, I went up, tied the pallets back, and took the weights off, so the gear train was completely free, and I pushed it round very slowly, by hand, through twelve hours. I could not find any friction, and when I re-started it, it stopped in the middle of the night. I was gradually becoming convinced that the friction was at the end of the gear train, so I took off the escapement rotor. I found that one of the rods in the lantern pinion had broken. (See photo.) I bought a metre of piano wire of the correct diameter (14 swg 2mm), and cut off 1% cm, and replaced the broken rod.The clock is now working again!
I am very puzzled as to why it should have broken after 137 years, since there is not much force on the pinion as it only drives the rotor. There must have been a fault in the metal.