When adjusting my GO766 RPM it seems to hit dead spaces as I turn the speed control knob to increase RPM. As I continue to increase, it finds itself again and power is returned. I know of another GO766 that will not go below 900 RPM. When starting up from zero it just runs up to 900 and will not go down, it will go higher but not below 900.
if it is still under warranty get griz to send you a new pot . If out of warranty ( I do not remember the pot's it's values) go on line and order two so you have a spare, they are pretty cheap. I got mine from radio shack before they went under is has been good since. It is not that big of a project to replace , but when you do see if you can work in as much slack as you can to make it easier. Of course unplug it.
Pete - Sounds like some of the windings in the potentiometer have broken. It's a known, occasional issue in a cheaply made part. Suggest you call Grizzly tech support and tell them what you're experiencing. They may send you one without charge, even though you're beyond the warranty period. If not, I think it's only $2.75. See this thread by Brice Rogers on replacing it: https://sawmillcreek.org/showthread....ew-G0766-lathe Also. this thread started by Mark Greenbaum: https://sawmillcreek.org/showthread....rol-is-whacked Perhaps Brice will see your post and jump in with a current suggestion for a more durable pot. Very useful to have an EE in the Group.
Thanks for your kind comment, David. The next time I replace a pot (that would be #3), I'm going to make some measurements to see if there would be any issue of reducing the pot from its current value (10K, wirewound, linear taper) to a 1K. The wire for the 10K pot is very very fine and having a metal scraper rubbing it everytime I adjust the speed wears it out. I have a theory that because a 1K pot will (probably) use thicker wire, that it'll last longer. I think that the internal circuitry is just a voltage source applied to the "top" of the potentiometer and the wiper acting as a voltage divider. The position of the pot determines the voltage sent back to the controller. So, I'm about 95% confident that this change could be made. End part 1
Part 2: Another approach would be to change from a wirewound pot to another type such as conductive plastic film. I read that now days, the conductive plastic pots have 10 to 20X the life of the wirewound ones. I would need to do some more research before selecting a manufacturer. But, spending 5 to 10 minutes every year or two (perhaps an exaggeration) to replace the pot isn't a big deal for me. I think that it took me 1/2 hour to replace the first one and less than 7 or 8 minutes for the second one. Right now I have little wire-nuts that make it very easy to replace the pot. I also have a spare pot. They are cheap from Griz and I buy two at a time. When I see if I can replace the 10K pot with a 1K pot, I'll post my results for others.
David and Bruce: Thank you both . I'll be calling Grizzly this AM. These pots must be very fragile. My lathe hasn't gotten so much use that I would expect a failure of this type at this time. The other GO766, the one that won't go below 900 RPM, has had VERY light use.
This was the first time I’ve asked a question on the Green Monster. I could have just asked my friend and fellow club member, David Roseman, but I thought I’d try the Green Monster knowing that David would respond. I’d like to thank Roger Chandler for setting up and managing this great resource. Within 24 hours I had responses, to include from David, confirming what I thought was the problem but more importantly telling me how to repair it. The instructions from Brice Rogers, link in David’s response above,, are most helpful. A few things I learned so others don’t have to: See posting that follows.
A few things I learned so others don’t have to: -Measure twice, cut once = Read twice and then read again. When it says loosen strain relief nuts ON THE BACK OF THE HEADSTOCK, it does not mean the nuts on the back of the sealed plastic speed control box!! -The 2, number 1 phillips screws recessed on the back of the speed control box are hard to access, you can’t see them and need a short screw driver. -You really do need the small gray wire nuts. -When pulling the wires back through at the end of your repair, be careful to keep the grommet from pulling out, it will be difficult to get it back inside the small fingers that the strain relief nut connects to. Both machines running smoothly.
Glad you got the issue taken care of Peter! I think the weakest part on the 0766 is the pot. That being said, I’ve had one since they first came out, and longer than anyone else here. My original pot still works just fine, but I do have two spares on hand if I ever need them. My G0766 has had fairly heavy usage over the last 3 years.
I've read that this pot will fit. It's still a wire wound pot but it's rated for more power. The original is only rated for 1 watt while this one is rated at 5 watts so it'll have thicker wire. For a couple bucks I doubt I would bother getting a replacement from Grizzly. https://www.amazon.com/WX050-Carbon-.../dp/B01GZWNW0G
