Gralab timer bogging down
I've got a couple of Gralab timers in my darkroom, the typical big black dial model which I believe is a 300. They were given to me and probably date back to the 1970s or early 80's.
One of them has developed a problem where it will work a few times and then start bogging down. For example, I might be able to process one roll of film without any problems and then at the end of the next 8-minute film development it will hit the last 20 seconds or so and slow to a crawl. After that happens the timer runs super slow and I can't use it anymore. Next time I come into the darkroom it will work fine until it bogs down again. When it is working it is still perfectly accurate.
Has anyone had this problem? Any suggestions for things to look for if I open it up?