Halls 6” gem cutting machine

Having issues with the trim pot variable resister not reading The led light isn’t coming on I’m sure you would think that the led would be on. Anyway if anyone could help that would be great. It’s a 6” halls Australia gem cutting machine

Thanks
Steven

Steven, is there any chance you could add a photo and highlight the led and trim pot mentioned in your request for help. I am an electronics tech that has an interest in gem polishing, and i did a little reading on the Omni / Hall faceting unit. I found a really nice description of this from around 2008 on the IGS pages but am not sure how close their description is to your machine.

David